The hydraulic model based on rich experience is characterized by high efficiency and good cavitation resistance performance; the physical dimensions and discrete parameters of vacuum pump is subject to multi-purpose optimization; the design point efficiency is treated as the optimized objective function with consideration of standardization, and main optimized parameters are carried out discretization treatment; the blade material is stainless steel with high cavitation resistance; the design of the diffusion guide blade of the submersible pump is studied and compared with the experimental results, and the guide blade is designed and arranged by taking full advantage of inlet circulation results.