Visa for dual Filipino-American citizen

I'm afraid you will still have to apply for the China visa with your US passport, since you have had sticker as an american before, or your application may be refused if using your filipino passport. But it all depends on the consular offcials. If you come acorss a kind person, you may be given a China visa with your filipino passport. To get the visa successfully, I still advise you apply for the visa as a US citizen.