The United States has a very high HDI and China has a medium HDI rating.
One reason that the United States has such a high HDI (Human Development Index) rating could be because it has a Constitutional Federal Republic government compared to China's Communist State government.
The United States total improved sanitation is at 100% while China's is only at 76.5%. The total improved drinking water for the population in the U.S. is at 99.2%, while China's is at 76.5%.
China had many 2 railways and the United states only has 1. Two common natural resources in China are coal and Iron ore. The united states two most common natural resources are coal and copper.
The living conditions in the countries can be very different. Most to all the houses in the United States are made of materials that will last long and have running water and access to food. China has most of the houses made of suitable materials but that is not the case in all places in China like how the houses are in the country side where some people have to have walk to get water and don't have electricity in their houses.