I am a US citizen born in HONG KONG, is there any different requrement to get a China Visa

Allan, do you have an HK passport? If you have one, actually you don't need the visa to mainland. You can apply for a Home Return Permit and use it to enter mainland. If you don't have an HK passport, you need to apply for a normal entry permit from the Commissioner Office of PRC Foreign Affairs Ministry in HK. The requirements are basically the same as you apply from overseas countries.