Abstract: Abstract:The conventional statistical meaning of international trade in services called BOP statistics was described in BPMS, which defines international trade in services as being between residents and non- residents of an economy. Based on GATS, the paper discusses the statistical universe of international trade in services and the content reflected by SNA （1993） BPM5 and MSITS （2002）. It extends the meaning of trade in services to cover services delivered through locally established enterprises, and the corresponding statistics＇designated as foreign affiliates trade in services statistics. Also discussed in the context of trade in services covers services that are supplied by individuals temporarily located abroad. Moreover, we study the correspondings among kinds of classifications concerned and finally estimate the size of China＇ s international trade in services according to GATS, which find that these years mode 4 develops quickly, and other modes are still the most part