Through the research of pump in hydraulic control unit (HCU) of electronic stability program (ESP), a design method that actively build up brake pressure without pre-pressure was established. After that, a simulation model in AMESim to analyze the structure parameters of the HCU of ESP was proposed, especially the influence to increasing pressure rate with different pump flows and motor speed parameters. Based on the above, the pump flow and motor type can be defined when the hardware was matched by ESP. Finally, a bench test was carried out to prove the function of the pump that could build up pressure without a prepressing unit. 