Itis notuntil 2002thatinternationalscholarsbegantostudytradeinserviceswithgravityequa-tion. Chinese scholars did not do the same study until 2009. Based on the gravity model，this paper dis-tinguishes and measures the determinants of trade in services and then estimates the export potential of China'stradeinservices.In the empiricalpartofthispaper，basicandexpandgravitymodelsareused， and four measurement methods are applied. The result shows that GDP，population，physical distance and FTAshowdif erentsignificancewhentheyimpactthetotal volumes oftradeinserviceandsub -sectors respectively.