On of the practical difficulties of high speed automotive hydraulic power steering is that the output exceeds the actual demands of the system, i.e., there is a substantial power loss. This paper discusses the configuration and the action principle of a new variable displacement of double-action vane pump, which consists of floating blocks. The pump belongs to an automotive hydraulic power steering system, and prosperous utilization is expected. In the meantime the mathematical and simulation model for hydraulic power steering of automobile were established and the Matlab Simulink simulation model was presented. Different parameters of pump are selected in simulating programming. The simulating results are analyzed and compared.