First of all it is not a "pure" race. Most Westerners will claim that all Chinese look alike, and they are afraid of the monolithic group of people that are Chinese.

In the first place the language describing Chinese is inaccurate. There are two meaning of Chinese
* a person from China, and I have met a Caucasian who rightly claims he is Chinese, because he was born in China.
* a person whose ancestors at one point hailed from China, but do not have or never did have Chinese citizenship.

Here is a video showing the ethnic song from Sichuan, illustrating one of the ethnic cultures in China.

This is excerpts from a Chinese person of Miao ethnicity:
* the current major race of china is called "Han", which is the name of a 2000 year old Dynasty.
* the Han do not have pure blood; it'a actually the decedants of many races merged together and they are proud of this point.
* during the Han Dynasty, the main race was called "Hua", other races were called "Yi", "Nanman", etc. That is why Chinese are still called "Hua Ren" today.
* "Hua", "Xia", "Xiqi" and some other races merged into "Hua".
* "Yi" means other races in west to China, "Nanman" are those south to China.
* there were differences, like back in that time, "Han" do crop planting while "Yi" do hunting.
* Later "Hua" was invaded by other races all the time likely every 500 years, the most famous are Mongolians and Manchus.
* one thing is all the races do live in China, so it's not wrong to call everyone "Chinese", and the nation is "peoples republic of China" not "peoples republic of Han.
* an example of how confusing it can get; Miao is a race in south-east China.
* we consider overseas Chinese as "Chinese expats", while Miao people could consider those oversea Miao as "Miao expats", so a person could both be "Chinese expat" and "Miao expat".
* you can claim to be any race of your family ancestors in china.
* if your aunt is Miao, your grand-uncle is Hui, your father is Han, you can claim legally as any of Miao or Hui or Han in China .. and some times we are proud to say "I'm a Miao but my father is a Han".
* well, in china minor races have benefits.
* in china minor races have more education opportunities, better policies, in order to "keep the culture". in chinese government there is no least-percentage for Han, but there is always a least-percentage for minor races according to local population.
* we accept the difference of races and we live well with the difference.