By using NCEP/NCAR reanalysis, NOAA Sea Surface Temperature (SST), merged precipitation from Climate Precipitation Center(CPC), and precipitation data from CMA, in recent 42 years, the main modes of variations of the Western Pacific Subtropical High (WPSH)from June to July and their possible impacts on the precipitation during the Meiyu period were investigated.Results show that the four leading modes are a zonally extended triple pattern(Ⅰ), a north-south dipole pattern(Ⅱ), an east-west dipole pattern(Ⅲ), and a central pattern(Ⅳ). Different patterns are affected by different anomalous circulation patterns in westerlies in the middle and lower latitudes. The anomalous circulation patterns in lower latitudes are related to the atmospheric response to the abnormal thermal forcing of SST Anomalies (SSTA). The SSTAs in the equatorial central East Pacific are favorable for WPSH to behave in a way with patterns of type Ⅰ and Ⅱ. If the remote forcing in earlier period of time is not so strong,the WPSH will be affected by the thermal forcing of the underlying surface over the Marine Continent or the Northwest Pacific, which is conducive to the occurrences of type Ⅲ and type IV patterns. The type Ⅰ,Ⅲ and Ⅳ anomalies are found to have possibly strong impacts on the precipitation in regions including Yangtze River, Yellow River,South China, Northeast China, and Japan. These results are helpful for better understanding the mechanisms of WPSH variations and finding clues to climate predictions.