A schematic diagram of digital displacement pump based on vector control and high-speed on/off valve control was designed. The control scheme of digital displacement pump was proposed. The mathematic model of digital displacement pump was set up. According to the control scheme and the mathematical model, the co-simulation model of digital displacement pump was established by using AMESim software and Simulink software. Then the influences on dynamic characteristics of digital displacement pump based on different parameters which were speed gain, applied load and control flow were analyzed. The results show that the overall performance of designed digital displacement pump have more substantial improvement, wide variable range, high control precision, fast response and quite ideal in energy-saving effect.