Abstract:Based on the NCEP data and outgoing longwave radiation (OLR) data provided by NOAA satellite observations, the paper analyzed the abnormal characteristics of western Pacific subtropical high (WPSH) during the storm rainfall over the Huaihe Valley and abnormal high temperature in the south of China from June to July in 2007. It is shown that the WPSH is stronger than normal and relatively stable in the north south movement.The shift in the east west direction is more obvious than in the south north direction. By analyzing the characteristics of vertical circulation field and wind vector on meridional plane, we find that the upward currents can be stimulated in the south and north of WPSH. The upward current in the north of WPSH stimulated the downward current in the center of WPSH at 700 hPa over the region. While the upward current in the south of WPSH plays a minor role on the downward current in the center of WPSH.The establishment of a blocking anticyclone in the mid higher latitude can intensify the WPSH. The strong and stable westerly jet in the middle latitude and the abnormal actively convection in the tropical region are conducive to the relative stability of the WPSH.