Currently I am holding a FAA ATP in USA, and realize that in Asia, most of the airlines require a ICAO ATP. Can some one please tell me what's the difference? if there is a major different, then how can I obtain an ICAO ATP?

Thanks

You have an ATPL issued in accordance with ICAO. It's an FAA one.
Need to convert it to the local ATPL of the country you'll be working in. Sometimes easy, sometimes more difficult.
Air Law exam and a flight test through to all local ATPL exams Flight test.

Where do you want to work?

I am very interested in South East Aisa, Taiwan or Singapore. I am grateful for your help.