Using the research result for ENSO events and their intensity during the past century by Wang Shaowu,et al.,the statistical relation between ENSO events and drought/flood over the Beijing area in the past century was analyzed.It's shown that there is the perplexed relation between ENSO event and drought/flood in Beijing.The corresponding relationship between the nature (warm or cool),intensity,beginning season,length of ENSO events and drought/flood in Beijing are complicated.Based on the data of ENSO events and the equivalent trrential rain days in Beijing,some statistical results were given.