Based on daily temperature (maximum, minimum, and average) data of 65 stations, spatial and temporal changes of extreme temperature events and the El Niño Southern Oscillation (ENSO) influence on the extreme temperature threshold over Yangtze River Delta were analyzed for the period 1960-2014. The results showed that in the last 55 years, the extreme temperature indices, i.e. summer days (SU), tropical nights (TR), warm days (TX90), warm nights (TN90), warm spell duration days (WSDI), and growing season length (GSL) have all increased significantly, and TN90 showed an increasing rate of 8.55d per decade. The extremal indices (TXn, TNn, TXx, and TNx) had increasing trends in the Yangtze River Delta region, and TNn showed an increasing rate of 0.53℃ per decade. The ice days (ID), frost days (FD), cold days (TX10), cold nights (TN10), and cold spell duration days (CSDI) have decreased significantly by 0.40 d, 4.03 d, 2.56 d, 6.06 d and 0.33 d per decade, respectively, and TN10 showed a decreasing rate of 6.06 d per decade. DTR has decreased by 0.11℃ per decade. For the spatial distribution of SU, TXn and TNx, all meteorological stations showed increasing trends during 1960-2014. TR, TX90, TN90, TNn, TXx, WSDI, and GSL showed increasing trends at 97%, 85%, 98%, 95%, 78%, 92%, and 94% of meteorological stations, respectively. ID, FD, TX10, and TN10 showed decreasing trends for all stations. For CSDI and DTR, 87% and 77% stations showed decreasing trend. Most extreme temperature indices show good correlation with latitude, longitude, and altitude. After the detected abrupt climate changes, extreme warm indices increased, and extreme cold indices decreased significantly. Overall, the effect of El Nifio on extreme temperature indices was greater than the effect of La Nina.