Based on the relevant reference data of the tropical cyclone (TC) in NorthWest Pacific (NWP) regions and the sea surface temperature (SST) from 1 950 to 2005, the general climatic features of the TC in NWP, the seasonal and interannual variations and the relationship with SST were analyzed. The TC int ensity, track, the formation regions and their relations were als o investigated. In NWP there are four areas where TCs frequently occur, i.e., th e northeastern area of South China Sea, eastern Philippine Sea, adjacent sea are as of t he Guam and the Marshall Islands. Among them the Guam area is the main origin wh ere the TC frequently occurs. The seasonal and interannual variations of TC ov e r NWP are obvious and closely associated with the local SST. The TC formation re gions shift westward and northward in warm years of SST and eastward and southwa rd in cold years. The northwest line of the TC formation location is well matche d to the monthly mean SST isotherm of 27.5℃. Most of TCs are formed in the area s where the monthly mean SST is equal to or higher than 27.5℃. The intensity an d the track of TC are associated with the TC formation regions. When the TC form ation regions move westward and northward, the TC intensity is lower and the TC tracks move northwestward, the number of TCs affecting eastern and northern Chin a seas may be increased. On the contrary, when the TC formation regions move eas tward and southward, the TC intensity is higher and the TC tracks move eastward and southward too, and the number of TCs affecting the southern China seas and t he seas of Japan may be increased accordingly.