Semu people are a general term for people from the western regions in the Yuan Dynasty. The word "Semuren" was popular in the Tang Dynasty, which means "ever-changing" and "various color names". Sometimes people with "rare surnames" are also called "semu people", that is, people with different surnames. The rulers of the Yuan Dynasty were Mongols, who were familiar with and in frequent contact with the Han people (including Jurchen and Qidan), while people outside the Han people were mainly called Semu people, sometimes called "Westerners".

Among the Semu people with different names, the Hui people are the most, so sometimes the Hui people are called Semu people. In addition to the Hui people, there are Wang ancients (in the area of Daqingshan, Inner Mongolia), Xixia people (also known as Hexi people, in the area of Ningxia and Gansu), Uighurs (that is, the ancestors of Uighurs, which were mainly distributed in eastern Xinjiang at that time), Halalus (south of Balkhash Lake in Central Asia), Khampa people (north of Aral Sea in Central Asia) and Qincha people (north of Black Sea in Central Asia). At that time, Europeans (called Francs or Zhilang people) were of course considered Semu people. At the end of Yuan Dynasty, Tao said that there were thirty-one kinds of semu people, which was not accurate, but it was conceivable that there were indeed many kinds of semu people, and the list was endless.