Abstract: In order to know the variation characteristics of acid rain and the effect of precipitation on pH value of acid rain in Fuling of Chongqing, based on the data of acid rain and precipitation in Fuling from 2005 to 2014, this paper used statistical method to analyze the monthly, seasonal and annual correlation between precipitation and pH value of acid rain. The results indicated that: the frequency of acid rain was 42.13% in Fuling, and dominated by weakly acidic precipitation; there was little strong acid rain since 2011; the lowest pH value in fall and the highest pH value in winter were observed, we also found the smallest pH value in June and the largest pH value in July; furthermore, the total precipitation, effective precipitation day, and heavy precipitation ratio influenced the monthly, seasonal and annual change of acid rain, which meant the variation characteristics of acid rain could not be illustrated by a single index; among the influencing factors, the heavy precipitation ratio had the most influence on pH value of acid rain. The above results show that understanding the variation characteristics of acid rain can provide a basis for preventing and mitigating its harm.