Abstract: soil mesofauna in 4 types of soil gradient in acidity was investigated in beach land of Eastern Shanghai in 1999.Relations between soil fauna and soil acidity were studied by using community parameters of species richness,individual abundance,diversity index and evenness.The results indicated that soil Collembola and Acarina were susceptive to soil acidity.Species richness,diversity index and evenness of Collembola community and species richness,individual abundance,diversity index and evenness of Acarina community well reflected soil pH,with correlation coefficients being more than 0.9 and around 0.85 for Collembola and Acarina,respectively.In conclusion,these community parameters of Collembola and Acarina can distinguish the soils with pH more different,Paranura sp.(Collemboa) can be used for indicating the soils with pH closer,while Hypogastrura sp.(Collembola) for assessment of the soil with pH more different and higher or under more stress conditions.