Abstract:During the autumn of 2018, the surface air temperature was below normal in West China but above normal in East China. And the distribution of precipitation in eastern China was “more in the north and south, less in the middle”. The precipitation was above normal in the central and eastern part of Inner Mongolia, Northeast China, the southern part of the south of the Yangtze River and South China, but below normal in the region from North China to the northern part of the south of the Yangtze River. In addition, the precipitation in the south of the Yangtze River and Southwest China showed obvious seasonal reverse distribution characteristics. By analyzing the causes for the climatic anormaly, we found that in autumn, ridge and trough activities in middle and high latitudes of Eurasia were frequent, the cold air was active, the western Pacific subtropical high (WPSH) was stronger and more westward than normal, the ridges of WPSH fluctuated greatly from north to south, and the southwest water vapor transport was stronger, resulting in the abnormal distribution of precipitation in eastern China. Further studies have shown that the sea surface temperature anomaly (SSTA) was the major extermal forcing factor for the climatic anomalies in the autumn of 2018. The El Ni〖AKn~D〗o type developed from the central Pacific type (CP) El Ni〖AKn~D〗o to the eastern Pacific type (EP) El Ni〖AKn~D〗o. The positive phase of tropical Indian Ocean dipole (TIOD) turned to the positive phase of South Indian Ocean dipole (SIOD). And there was obvious response of the East Asian subtropical atmospheric circulation to the SSTA in the Pacific and Indian Ocean in autumn. Therefore, the evolution of El Ni〖AKn~D〗o and the SST in the Indian Ocean and their influence on the East Asia atmospheric circulation, together with the seasonal adjustment of the anomalous circulation in the middle and high latitudes in Eurasia, led to the obvious east west interseasonal changes of precipitation in sou thern China.