The influence of the climatic variation of rainfall on the evaluation of precipitation enhancement effect was analysed. The results show that the evaluation of precipitation enhancement effects is influenced by the climatic variation of rainfall. In the abundent rainfall years in Fujian Province,the positive false effects are obtained,and in the lacking rainfall years,the negative false effects are obtained. The false effects of sequentail experiment are higher than that of other ones. The multifactor gradational experiment decreases the influence of climatic variation of rainfall on the evaluation of the effects.