Abstract: In this paper, taking the green fodder harvester throwing cylinder as the research object, aiming at the problem that the throwing cylinder is broken in long-term operation, numerical simulation is used to calculate the flow state in the throwing cylinder and make prediction on the wall wear. Under the designed working condition, the inlet velocity of the throwing cylinder and the size of the chopped straw are taken as the boundary conditions of the flow field calculation to obtain the velocity and pressure distribution inside the cylinder; on this basis, the DNV wear model is chosen to obtain the distribution characteristics of the wear rate of the wall of the throwing cylinder. Then a method to enhance the wear resistance of the throwing cylinder and extend its service life is proposed. The numerical calculation method is applied to the study of flow characteristics and wall wear prediction in the throwing cylinder of green fodder harvester, which provides theoretical basis for the optimization design of the flow path of the throwing cylinder and the evaluation of the wear state as well as the design of anti-wear.