Abstract: Jinyun mountain is located in the acid rain area of southwest China. In recent years, the acidity and frequency of acid rain are getting higher and higher,  and there is also a trend of transformation from sulfuric acid rain to sulfuric acid-nitric acid mixed rain and nitric acid rain.The effects of acid rain type change on photosynthetic and physiological characteristics of vegetation in jinyun mountain were studied to provide basic data for vegetation construction and cultivation of acid-resistant tree species in disasterareas. Two years of Pinus massoniana seedling in jinyun mountain were treated with three acid rain types (sulfuric acid, nitric acid and mixed), and three acid concentration (pH2.5, pH3.5, pH4.5) processing by pot experiment for four months, supplemented by the pH value of 5.7 distilled water as control group, the net photosynthetic rate, intercellular  carbon dioxide concentration, transpiration rate, stomatal conductance, antioxidant enzyme activity, chlorophyll content and malondialdehyde content were determined. The results showed that :(1) The three kinds of acid rain had effects on the photosynthetic physiological characteristics of Pinus massoniana. The higher the concentration of acid rain, the more obvious the inhibition effect on the photosynthetic rate.The pH value of 3.5 was the acid value that affected the sharp changes of all indexes of Pinus massoniana. SAR and NAR acid rain with pH value of 3.5 had serious inhibition on the growth of Pinus massoniana plant height, and the inhibition rates were as high as 53.49% and 54.99%.(2) Different types of acid rain stress inhibited the formation of chlorophyll in Pinus massoniana leaves, and the main expression was SAR>NAR>MAR. The chlorophyll content decreased with the increase of acid rain concentration.Acid rain can promote the increase of malondialdehyde content, and the lower the pH value, the higher the content of malondialdehyde.(3) Acid rain could stimulate the activity of antioxidant enzymes in plant leaves. Different acid rain had different effects on the activity of antioxidant enzymes in leaves, which showed NAR>SAR>MAR.The three types of acid rain all had effects on the photosynthetic physiological characteristics of Pinus massoniana seedlings, and the effects of different types of acid rain were different under different gradiens. By comprehensive comparison, it was found that MAR acid rain had less inhibitory effect than the other two single acid rain, and NAR acid rain had the largest effect on Pinus massoniana seedlings.