The crossbow traps in the tomb scene were based in reality. According to Chinese archaeologists, the excavation of the Qin Dynasty Terracotta Army in Xi'an is progressing so slowly, partially because the site is filled with similar traps.

The filmmakers originally considered bringing back Arnold Vosloo as Imhotep, except this time, he's a last-resort ally who helps the heroes defeat the Dragon Emperor. Vosloo hated the script and didn't want to make a Mummy movie without Stephen Sommers, so he declined to return. Oded Fehr was also asked to reprise his role as Ardeth Bay. Fehr declined because Imhotep was not to be in the film, and had felt that if there was no Imhotep, then Ardeth Bay had no point or reason to appear in the movie.

Rachel Weisz did not appear in this third installment of "The Mummy" films, and instead, her character, Evy, was played by Maria Bello. There were differing accounts as to why this happened. According to director Rob Cohen, it was because Weisz refused to portray someone with a 21-year-old son. Weisz simply did not like the script enough to sign on. Rumors circulated that Weisz chose not to be separated from her (toddler) son at the time, but she has since made it clear that this had no impact on her decision whatsoever, and pointed to two other films that she starred in that very year.

Since Jet Li was only available for a part of the shoot, it was decided that the Emperor would be either a rotting mummy or encased in terracotta in most of his scenes. In that way, Li could play the Emperor in the flesh, and the remainder of his role would be done by a CGI character.

In the closing scene, a screen text reveals that mummies were soon thereafter discovered in Peru, a possible stinger for a sequel (Peru is home to the ancient Inca civilization, which also mummified their important members). There was indeed going to be a third sequel titled "The Mummy 4: Rise of the Aztecs", but since Aztecs are native to Mexico, it probably would not have been set in Peru. Brendan Fraser and the cast of the third film had signed up for the sequel, and Antonio Banderas would have played the main antagonist. However, the film was canceled in favor of the reboot The Mummy (2017), which was meant to be the first chapter in the 'Dark Universe', interconnected movies featuring the classic movie monsters such as the Mummy, Dracula, Jeckyl and Hyde, the Wolfman, the Creature from the Black Lagoon and Frankenstein. However, due to the critical and commercial failure of The Mummy (2017), all other proposed movies were eventually scrapped.

Continuity

In the museum scene, Choi grabs Evie and wraps her arm around Evie's neck. Evie gets away. In the next shot, Choi's arm is around Evie's neck again.

When Alex and Lin are under the Emperor's wagon during the chase, Alex turns himself around, and is dragged in the street for a fair distance while Lin tries to reach him to pull him up. When she succeeds, the back of Alex's shirt is shredded, and a protective pad is visible through the tears. In the next shot, his shirt is intact.

Just before the battle at the temple bridge, Rick has a Thompson Sub-Machine Gun loaded with a 50-round drum. When the battle begins, the Thompson has a 30-round stick magazine.

When Zi Yuan cursed the emperor and his soldiers, as the curse processed at the beginning, we see his sword. When asked what she did to him, moments later after Zi Yuan manages to escape and told him that she cursed him and his soldiers. His sword vanished.



Factual errors

In ancient China, oracle bones were turtle shells that were heated during divination, the cracks that appeared across Chinese characters written on the shells were then interpreted to foretell the future.

The Bristol Beaufighter shown being flown by Cunningham, has two seats side-by-side in the cockpit. No variant of the Beaufighter had this seating. They were all single pilot seat only.



Incorrectly regarded as goofs

When the Emperor is first turned to stone, both arms are raised up and he is slightly hunched down. When he is unearthed, he is encased in a different Terra Cota warrior who is standing straight, one hand straight out, grasping the chariot's reins. However, when he breaks out, his hands are shown straight up and it is clear he is trapped inside another statue in his original position.

When Evelyn discovers the bullet in the trout, she pulls it out of her mouth. In the next shot of the left side of her face, she pulls the bullet out again. However, given Rick's personality, it is quite possible that he shot it twice.

The bullet Evelyn pulls from her mouth is compressed, as though it had struck a solid object. A close-range shot would have passed straight through a trout, unless it first went through water on the way to the trout.

In the beginning of the movie, General Ming was ripped to pieces by horses after having been chained by both arms and legs (the scene cuts away before any actual dismemberment). While it may seem that he would have lost a minimum of three limbs in the process, he is shown later with only one arm missing. However, if one looks at historical accounts of similar executions, horses alone were often insufficient to complete the dismemberment. For examples, see Robert-Fran?ois Damiens or T?pac Amaru II.



Revealing mistakes

In the Himalayas, a shot of a running soldier's foot clearly shows sand, not snow.

Evelyn Carnehan-O'Connell is supposed to be as British as John Bull, but in many scenes her voice sounds like an American actress attempting, with some difficulty, to affect a British accent.



Anachronisms

At the beginning of the movie, the Dragon Emperor is shown planning his campaign on a model of China which has the Great Wall portrayed on it, even though the Dragon Emperor himself built the wall AFTER the campaign.

The drum set in the nightclub is not from the 1930s. Some of the hardware (ex. cymbal stands) was not available until the 1980s.

A tan 1949 Austin passes in front of a bookstore in 1947.

During the 1947 Chinese New Year celebrations, a black Dodge four-door sedan has hubcaps from the late 1970s.

The dancing girls in the nightclub have plastic straps on their bras.



Errors in geography

When we first see Rick O'Connell (Brendan Fraser) he is apparently fly-fishing in a river in Oxfordshire. However, the visible geology of the river is not found in Oxfordshire (exposed tilted rock beds, pebbled river beds). This is more likely either elsewhere in the UK, or more likely, a location in the US.



Plot holes

Even though the emperor buried his enemies and slave workers under the Great Wall, the bodies would not be buried alongside their weapons/tools.



Character error

On the mountain, Rick says he had more experience with mummies. Alex says that he only killed one. Rick then says it was the same mummy twice. Both are wrong. First, Rick killed many mummies in the previous movies--Imhotep and many of his priests. Second, Rick only killed Imhotep The Mummy (1999), the underworld spirits killed Imhotep in The Mummy Returns (2001).

In The Mummy Returns young Alex has an English accent like his mother however in this movie an older Alex as an American accent like his father.

The Terracotta Army are called "mummies" throughout. Yet not one character in this movie goes through the mummification process. The only mummy we see is the fake Emperor that Lin stabs.

Before the Himalayan fight scene, when Rick and Alex are comparing weapons, Rick pulls out a Colt 1873 Single Action Army. He refers to this gun as "The Peacekeeper." The correct term is "The Peacemaker."

The orchestral chimes behind the drummer are turned around backwards, facing the curtain behind the band.