Abstract:The setting of initial rainwater storage tank has gradually become one of the most economical and efficient means to solve the initial rainwater pollution. Combined with the actual engineering case of the initial rain storage tank of Tianshan sewage treatment plant, this paper expounds in detail the functions and design points of the initial rain storage tank in the urban drainage system, in order to provide important theoretical support and experience reference for the optimal design of the initial rain storage tank in the later stage.