Abstract: According to the data of 5 atmospheric precipitation monitoring sites in Kunming from 2015 to 2019,from the aspects of precipitation pH,rainfall,conductivity,inter-annual variation of ion concentration and the correlation between ions,the trend of atmospheric precipitation change and ion characteristics in Kunming are studied. The analysis results showed that the p H value of the precipitation in Kunming from 2015 to 2019 fluctuated slightly,all above 5. 6,and acid rain has not occurred. Except for 2019,the conductivity of the remaining 4 years showed a downward trend. In terms of the inorganic ions in precipitation,the concentrations of SO₄^2- and Ca²⁺ accounted for the largest proportions,respectively 34. 5% and 29. 3%; SO₄^2-/NO₃^- showed a downward trend,indicating that the rainfall type in Kunming gradually evolved from sulfuric acid to mixed sulfuric acid & nitric acid.The Pearson correlation analysis of the ions in the rainfall in 2019 showed that the correlation between SO₄^2- and NO₃^- is good,indicating that the precursors（ SO₂ and NO_x） of these two had a common source and a similar chemical behavior in the precipitation process.