Based on Xichang, Panzhihua and Wenjiang's nearly seven years acid rain monitoring data, the month and annual variation characteristics of acid rain in three places are analyzed. The results shows that: in Xichang, there is weak acid rain pollution all year in Panzhihua, there is no acid rain pollution from January to March and weak pollution from April to December in Wenjiang, there is strong acid rain pollution in spring autumn and winter and weak pollution in summer The value of Xichang's PH has increasing trend in recent years, while the trend of Panzhihua and Wenjiang's Ph is not significant. Through comprehensive comparison, Wenjiang belongs to heavy acid rain area, Panzhihua and Xichang belong to light acid rain area.