Abstract: Acid rain characteristics in Kunshan were analyzed by statistic method based on acid rain monitoring data and meteorological observation data from April 2007 to March 2009. The results indicate that acid rain frequency is more than 80% in recent two years in Kunshan. The pH value of average annual precipitation is less than 4.70 in Kunshan, so it belongs to the serious acid rain area. Acid rain pollution in 2008 is more serious than that in 2007. Acid rain frequency in autumn reaches the highest, followed in winter and spring, and it is the lowest in summer. Acid rain intensity is related to meteorological factors such as wind direction, wind speed, precipitation and haze.