Let me explain. China, due to the large amount of manufacturing, has a pretty high GDP (GDP meaning how much money the country as a whole makes.) However, factory work tends not to pay as well as many of the più white collare jobs we tend to see in più developed countries. As such, despite the amount of manufacturing that goes on there, the GDP per capita is low (GDP per capita basically meaning how much money the average person in a country makes.)
Basically, the amount of things made in china is offset da the amount of people there, and so the people in China tend to be a little poor.