The χ²test is performed on the data set of daily precipitation and temperature of Shanghai, Hangzhou and Nanjing stations in the Yangtze Delta. The results indicate that there is no correlation between ENSO and the annual precipitation, seasonal precipitation and annual maximum temperature (not reach the significance level of 90%). If the ENSO is categorized into 3 types however, the results indicate that the El Nino type Ⅰ leads to more precipitation than normal year, about 15.6% more than the normal year, with lower occurrence possibility of higher-temperature climatic conditions; the El Nino Ⅱ type leads to precipitation 20%-30% less than that of the normal year, with higher occurrence probability higher-temperature climatic conditions.