The electronically controlled fuel injection system of the diesel engine has multi-disciplinary characteristics and strong coupling. The programming method based on a mathematical model cannot be applied to the fuel system with a diversified structure arrangement. With the rapid development of hydrodynamics, more and more simulation software is applied in the actual research. Hydsim simulation platform is one of the best software for the simulation of the electronic control injection system. In this paper, the Hydsim simulation platform is used to simulate the electronic control injection system, and a test-bed for verification is built. Based on the experimental results, the injection characteristics of high-pressure common rail are studied. The validity and accuracy of the simulation model are verified by comparing the simulation value with the test value and the standard value. Finally, the influence of the structural parameters such as the inlet and outlet orifices and control pistons of the injection system on the injection characteristics is analysed, and the selection principle of each parameter in the system design is proposed, which provides a reliable basis for the structural optimisation.