The constant flux blanking plug is a downhole flow control device used in the separate layer water injection system of oil-field, its flow characteristic and reliability are the most important matters that people care about. So these performances of the constant flux blanking plug are analyzed by numerical methods here. The dynamic model of the constant flux blanking plug is established by bond-graph, then the simulation is made by the 20-SIM software. The influence of local flow field is studied by CFD (computational fluid dynamics), with which some different valve spools and pockets are compared. The discrete particles’ trajectories are analyzed by the Lagrangian method, and the particle erosion rates of different materials are calculated with Bitter’s erosion model. All the simulation data show that the structure and material have great influence on the flow control precision and reliability which need to improve at present. The simulation results are verified through ground or field tests in the end.