Abstract: Based on the close reationship between geothermal vortex (henceforth GV) in soil temperature field in 320 cm depth and rainy area in mainland of China, the amount of summer rainfall for was predicated by us many years and the results are inspiring. In this paper, the soil temperature data in both sides of Taiwan Straight (henceforth BSTS) are analyzed with the similar way and a seasonal rainfall prediction program is put forward. Statistic results show that the GVs here have it's regional charact eristics: the average scale of GVs here is 480 km, which is slightly smaller than that in the scale of GV in mainland (580 km). Moreover, the mean lasting time of GVs here (4.0 seasons) is 1.8 seasons shorter than in the mainland. Most of the GVs, mainly move from the north and west boundaries of the analyzed area, move eastw ards to the west Pacific with a mean speed 215 km per season that is faster than the moving speed of GVs in mainland. Most of the GVs are accompanied by a positive abnormally rainfall area in the same seasons and in most cases, the distance between the center of GV and center of rainy area are no more than 100 km. However, when strong earthquakes (Ms≥6.0) occurred in Taiwan, this area may suffer from drought, so, the predict results must be corrected during such conditions.