Abstract: The mid summer and autumn droughts refers to droughts that occur in summer or autumn, which occur frequently in Chongqing and cause economic losses. Based on daily precipitation data of 34 national meteorological stations from July to September during 1965-2016 in Chongqing, the temporal and spatial variation of the mid summer and autumn droughts were analyzed by Standardized Precipitation Index (SPI) and precipitation anomaly percentage index (PA). By Spearman rank correlation method and stepwise regression method, factors with strong correlation were screened out from climate factors. The results showed that the frequency of continuous mid-summer and autumm droughts from July to September was 7.7%. The drought synchronization accounted for 15.4% in July-August and 13.5% in August-September. The drougnts varies greatly in Chongqing from 1960s to 1970s, the mid summer and autumn droughts was getting more serious; since the middle and late 1980s, droughts and floods have appeared alternately; in the 21st century, severe summer and autumn droughts occurred frequently. After the 1960s, the annual average total number of drought xun (ten-days) increased from 3.3 to 4.1 xun, and the number of coutinuous drought xun increased from 2 to 2.5 xun. From 1965 to 2016, the annual average total number of drought xun in the western region was 3.6 xun, and the number of coutinuous drought xun was 2.2 xun, which was relatively small. After 2006, the mid summer and autumn drought was mild in the southeastern and northeastern regions, and severe in the middle and the western regions. The mid summer and autumn droughts in Chongqing are closely related to the circulation and SST anomalies. The main correlated factors include Northern Hemisphere subtropical high ridge position index, Northern Hemisphere subtropical high northern boundary position index, the NINO A SSTA index and the Kuroshio current SST index. The SPI of Chongqing in July was negatively correlated with the Northern Hemisphere subtropical high ridge position index in January of the same year; the SPI in September was negatively correlated with the NINO A SSTA in April of the same year. The research results can provide a theoretical basis for ensuring water security and realizing the scientific allocation of water resources in Chongqing.