During the starting process of diesel engine, the variable external environment and the working characteristics of high pressure fuel pump were likely to cause the rail pressure rise hysteresis and abnormal fluctuation which directly affected the starting performance of engine. Controlling the starting rail pressure precisely was hence the key to improve the overall performance of engine. The control model was established to control the starting rail pressure and its combined simulation with the physical model of high pressure common rail injection system constructed with AMESim software verified the controller performance . The control model built the rail pressuremetering valve (MeUn) flow calculation model based on the conservation principle of fuel mass from and into rail pipe and realized the highprecision rail pressure control instead of PID controller. The cosimulation iterative calculation results show that the startup pressure establishes rapidly, the rail pressure does not overshoot in the transient conditions and the rail pressure fluctuation at idle is within  1 MPa.