Abstract: Using the Community Atmospheric Model Version 3.1 (CAM3.1) provided by National Center for Atmospheric Research (NCAR), the influence of the East Asian subtropical zonal land-sea thermal difference on the spring persistent rains is studied. The results show that the monthly sea surface temperature over the western Pacific (15°—35°N, 120°—150°E) are two months ahead of schedule, the seasonal conversion of the East Asia—the western Pacific subtropical zonal land-sea thermal difference is delayed, and the thermal difference between the East Asia and the western Pacific in spring is decreased. Under this condition, the intensity of the southwest winds at 850 hPa over East China in March and April decreases, and the rainfall over the region to south of 30°N decreases during the period from March to April, the remarkable decreasing periods are mid-March and mid-late April. The result shows that the intensity of spring persistent rains decreases due to the little land-sea thermal difference. The important role of the East Asian subtropical zonal land-sea thermal difference on the spring persistent rains over Southeastern China is verified. As far as the mechanisms are concerned, the results are as follows.When the land-sea thermal difference of subtropical zonal is minished, the intensity of vortex over the southeastern Tibetan Plateau weakens and then the geopotential difference between this vortex and the western Pacific subtropical high minishes. The western Pacific subtropical high over the middle and low latitudes weakens, and the intensity of the southeast wind decreases over the region to north of the western Pacific subtropical high. Therefore, the southeast warm moist airflows decrease and the convergence intensity of the moisture flux divergence weakens. Under this general circulation conditions, there are no heavy spring persistent rains.