With three-dimensional particle simulation software, a new type of 18 vane 5.8 GHz magnetron has been simulated. The differences between explosive emission and beam emission are compared. Using beam emission models, the influence to the magnetron characteristics by the cathode current destiny can be obtained. At the same time, the magnetic field distribution can be obtained using simulation software FEMM. On this basis, hot test simulation has been performed under non-uniform magnetic field condition. With the research provides a basis for developing 18 vane 5.8 GHz magnetron.