Abstract:In order to conclude the reasons of climatic anomaly and improve the skill of climatic prediction, the observation data and physical mechanism diagnostic method were used to analyze the climatic anomaly reasons in 2010. Results showed that the climatic anomaly in 2010 ranked the first within recent 10 years and the abnormity of ocean and atmospheric circulation features may lead to that. A moderate El Nino event occurred from June of 2009 to April of 2010 and followed by La Nina event from July of 2010. The tropical Indian Ocean sea surface temperature anomaly (SSTA) experienced two important periods: from basin wide warming to negative Indian Ocean Dipole (IOD) mode, and North Atlantic SSTA was characterized as triple mode in the same period. Due to the influences forced by SSTA and interaction between ocean and atmosphere， the atmospheric circulation over the Northern Hemisphere showed the dominant anomalies which have been featured as response as follows: subtropical high over the West Pacific (SHWP) was stronger than normal and further west to its normal position because of El Nino event before October of 2010， and afterwards it was weaker than normal and further east to its normal position due to La Nina event, and the location of its ridge line also showed significant stage characteristics. The strength of the South China Sea summer monsoon was the weakest since 1951 and East Asian monsoon was weaker than normal； Blocking highs were located over middle high latitudes in Boreal summer. Furthermore， the Arctic Oscillation ranked the extreme negative phase in 2009/2010 winter within 60 years. SSTA forcing and internal atmospheric dynamic processes may lead to the climatic anomaly in China in 2010.