Technically, the country that the story is set in was not known as China; instead it has been known as Bei-Wei, "the northern Wei"(https://en.wikipedia.org/wiki/Northern_Wei), to its later generations.
The capital city of Bei-wei was Luoyang(洛陽) instead of the modern-day Chinese capital Beijing(北京).
Given that not every Chinese knows the historical details of the Ballad of Mulan, which the movie is based on, let alone foreigners, it is a difficult decision for the writers to find a balance between making a movie that appeals to as many people as they can AND reflects all the historical details/accuracies.
Most of the details in this movie are off-the-chart wrong, such as:
- Mulan's family home, a dome-shaped structure, a tulou. As this kind of dome-shaped houses were predominately seen in the South, which was not part of Bei-wei.
- The supreme leader of Bei-wei would have been referred to as a Khan rather than an Emperor.
- The catapults were way ahead of its time.
What this movie got right:
- There are two direct references from this movie where they quoted from the Ballad of Mulan; 1st time is Mulan talks about there is little difference between a running male bunny and a running female bunny; 2nd time is Mulan and her fellow soldiers talk about their fiancees, they describe their fiancees as having spring-onion shaped fingers and etc.
- When Mulan and her fellow soldiers arrive in their camp for the first time, we see the name of the camp as 折衝府, which is more or less accurate for that era.
- The enemy Mulan fights against are Rouran （柔然）, as accurately stated in the movie.