In the present study,based on the CN05.1 gridded rainfall data and the NCEP/NCAR reanalysis for the period of 1961-2016,the interdecadal change of autumn rainfall in western China (WCAR) is investigated.The results reveal that the WCAR shifted from a positive phase to a negative phase in the mid-1980s.After entering the 2010s,the WCAR tends to increase again,with the increasing amplitude becoming even greater than that before the mid-1980s.Next,the physical mechanism responsible for the interdecadal change in the WCAR is further explored from the perspective of large-scale atmospheric circulations,in particular focusing on the similarities and differences in the atmospheric circulations for the increase of the WCAR after the 2010s and before the mid-1980s.During these two periods,in comparison with the negative phase of the WCAR,both the Lake Balkhash trough and Asian sea level pressure are strengthened,favoring the southward outbreak of cold air from the high latitudes into western China.Meanwhile,the southerly anomalies prevail in the lower troposphere of East Asia,thereby benefiting from the transport of water vapor from the low latitudes toward western China.In addition,the East Asian jet stream shifts northward,providing favorable dynamical conditions for the occurrence of the WCAR.Under such a configuration,the WCAR is strengthened.With respect to the counterparts before the mid-1980s,the blocking over Europe and trough over Lake Balkhash are both much stronger,which may cause more cold air from the high latitudes to invade western China.At the same time,more warm-moist airflows from the Indian Ocean in the Southern Hemisphere are transported toward western China.Finally,it is shown that more cold air and warm-moist airflows which are encounter in the targeted region contribute to the greater rainfall occurring after the 2010s than before the mid-1980s.