Abstract:  Abstract;The mesoscale atmospheric numerical model is used to study the tropical cyclone activities in the western North Pacific under the background of global warming.Two sets of experiments arc carried out to simulate tropical cyclone activities in the present and future climate, respectively. Each set of experiment includes cyclones.The National Center for Environmental Prediction rcanalysis data averaged from 1971 to 2000 are used as initial and lateral boundary conditions for present climate, and the U. S. National Oceanic and Atmospheric Administration’s data from 2031 to 2060，which is the result of geophysical fluid dynamics laboratory’s CM2. 0 with the A2 scenario, arc used as initial and lateral boundary conditions for the future climate.The model results show that the tropical cyclones enhance significantly under global warming. Compared with current climate, the tropical cyclones generated in the west part of the Western North Pacific arc stronger than those in the cast part. The tropical cyclones in the future move more cast than those in present.Tropical cyclone activity is closely related to large scale atmospheric circulation, In the future, the enhancing of tropical cyclones in the west of 130?E is mainly due to the increasing of sea surface temperature in this region, and the weakening of tropical cyclones near the south of 5?N nis related to the change of vertical wind shear and relative humidity in the correspond area.The change of the tropical cyclone track is related to the enhancement and the south movement of the west Pacific subtropical high.