Abstract: Based on the acid rain pollution status in Guangzhou area between 1996 and 2000,and compared with the results between 1986 and 1990,by classification statistics and multi-factor linear regression,the basic feature of acid rain pollution and the main factors that concerned precipitation acidity have been studied.The conclusion shows that in the precipitation chemical composition the proportion of SO₄^2- is the biggest,and the influence of NO₃^- on precipitation acidity is more important. The precipitation acidity has basically been decided by the two ions.For reducing precipitation acidity in Guangzhou area,while eliminating contamination of sulfur dioxide,controlling the contamination of nitrogen oxide is significant.