Anomalies of ocean and atmospheric circulations were analyzed and their impacts on temperature and precipitation anomalies were discussed. It is found that the warm condition was observed in the tropical central eastern Pacific Ocean during July to August 2012 and then it changed into normal condition, following the La Nina event which ended in March 2012. As a response of circulations to the warm oceanic condition, the western Pacific subtropical high was stronger and extended further west, controlling most southern part of China and causing temperature higher and precipitation less than normal there during September to October. From August to September, significant Indian Ocean dipole with a positive phase persisted in tropical Indian Ocean. Then, an anomalous anticyclone was excited over eastern tropical Pacific Ocean, with southwest airflows along its northwest edge affecting Southwest China and resulting in obvious autumn rainy season in its southern part. In 2012, onset of South China Sea summer monsoon was 1 pentad earlier than normal and the ending was 2 pentads later than normal, and the intensity was weaker than normal. And East Asian summer monsoon was observed the 4th strongest since 1951. Under the impact of anomalies of ocean and atmospheric circulation, colder than normal winter of 2011/2012 and autumn of 2012, warmer than normal spring and summer of 2012 appeared in China. Summer precipitation distribution shows more than normal precipitation in northern China and less than normal precipitation in southern China.