Do Hong Kong citizens living in the USA need a visa to enter china?

You don't need a visa to enter China from USA, you can use the Home Return Card to go to China.

Thank. This will save me the expensive visa fee. However, if my US passport has different name in the Home Return Card, will it cause any problem or inconvenient?

Please don't worry, the immigration officer just check the Home Return Card (Mainland Travel Permit for Hong Kong and Macau Residents), to avoid trouble, you'd better go to Hong Kong first, then enter Mainland China, generally speaking, it is ok for Home Return Card Holders to come to Mainland China directly from overseas, however, sometimes, if you face a strict immigration official, you will be denied to use Home Return Card to enter Mainland China from overseas.

Thank again. I used to enter china thru' Hong Kong by using Home Return Card. However, this time I try to save some time by taking connectiong flight. What is the worse scenario/consequences if I meet the strict immigration officer?

If you enter China from US directly, you may be asked for a China visa even if you meet a kind officer, so I still advise you enter China through HK. Although it will take longer time, but you don't have to apply for any visa.

thank Tyler