Based on the daily precipitation data in Ningxia,the NCEP/NCAR reanalysis data and NOAA sea surface temperature(SST) data from 1961 to 2015,this paper analyzes variation of the days of extreme precipitation(DEP) in Ningxia in summer and its causes.Results show that:(1)DEP in Ningxia in summer in the past 55 years has been slightly reduced,but the abrupt change of the variability occurs in 1994 from big to small.Variations of DEP in each month are different.In June,the abrupt change of DEP occurs in 1982,and DEP increases significantly after 1982.DEP in July is slightly decreasing.In August,the abrupt change of DEP occurs in 1995,and DEP decreases significantly after 1995.(2)The dipole pattern in North-Northeast China and the western Pacific at 500 hPa in June,the teleconnection patterns in West Siberia-Mongolia-subtropical China and EAP at 500 hPa in August,as well as wind field at 700 hPa over Ningxia with anomalous easterlies in June and northerlies in August,are the direct reasons leading to the extreme precipitation events.(3)The positive SST anomalies over the Philippines in June are favourable to the "+-" dipole pattern in North-Northeast China and the western Pacific at 500 hPa.The negative SST anomalies over the tropical eastern Pacific in August are good for 500 hPa West-low-East-high height distribution pattern in China,which excites EAP teleconnection wave train.The combination of cold air and water vapor conditions results in the frequent occurrence of extreme precipitation events in Ningxia.