The aid coming to China is miniscule as compared to the aid it provides to other low-level developing countries. Most of the aid to China comes through UN programs, for which any country could be applicable.
Let's not forget that China is a major developing nation with lots of development aspects be to be fully realized.
The US aid has been declining for years and it was around
$6 million in 2013. It must be much lower at the moment. I am not sure where it went to but China has since increased supervision so that the allocated funds would not be politicized for selfish geopolitical interests.
As for China's aid:
"From 2010 to 2012,
China appropriated in total 89.34 billion yuan (14.41 billion U.S. dollars) for foreign assistance in three types: grant (aid gratis), interest-free loan and concessional loan.
Grant is mainly offered to help recipient countries build small or medium-sized social welfare projects, and to fund human resources development cooperation, technical cooperation, material assistance and emergency humanitarian aid. In the three years, China provided 32.32 billion yuan of grants, accounting for 36.2 percent of the total assistance volume.
Interest-free loan is mainly used to help recipient countries construct public facilities and launch projects to improve people’s livelihood. In the three years, China offered 7.26 billion yuan of interest-free loans, taking up 8.1 percent of its foreign assistance volume.
Concessional loan is mainly used to help recipient countries undertake manufacturing projects and large and medium-sized infrastructure projects with economic and social benefits, or for the supply of complete plants, machinery and electronic products. In the three years, the concessional loans China provided to other countries amounted to 49.76 billion yuan, or 55.7 percent of its total assistance volume in the same period."
http://english.gov.cn/archive/white_paper/2014/08/23/content_281474982986592.htm