The structure and operating principle of a novel electrical servo variable displacement piston pump were described. The pump components and the whole simulation models were built based on AMESim software. The simulation analyses of its flow rate, flow rate-pressure and variable displacement adjustment characteristics were carried out. The results show that the designed electrical servo variable displacement piston pump has good performance, it can meet the requirements. The system simulation model built with AMESim software has higher credibility, it can well reflect the actual operation of the system, so the system optimization design and control algorithm implementation can be guided through simulation.