Precipitations in North China were 45% more than normal during July 2012, accompanied with serious flood disasters. Utilizing precipitation data in China and other data, the characteristics of the anomalies and the possible causes ware analyzed. The results show that it might be attributed to the influence of multiple factors. On the 500 hPa level, the large scale circulation exhibits “two ridges and one trough” pattern over mid high latitude of Eurasian Continent. The northward shift of the western Pacific subtropical high is also detected. Under this circumstance, the cold and the warm air converge strongly over North China, causing the serious precipitation anomalies. Further study shows that the SST of the equatorial western Pacific Warm Pool remains abnormally warmer in July 2012, generating strong convective activities and driving the subtropical high to north. As a result, the subtropical high shifts northward. On the other hand, affected by the positive SSTA in the North Pacific, an anomalous anticyclone circulation prevails over the northeast of East Asia and North Pacific region, causing the subtropical high stretching towards north.