Marine silicon-controlled-rectifier (SCR) shaft generator is driven by ship main propulsion shaft. Firstly, the structure of SCR shaft generator is introduced and its characteristics of power supplying both in normal operation process and in output decrease process are analyzed. Then dynamic mathematical model of field current control process and that of inversion angle control process of an SCR shaft generator are established. Afterwards, the simulation results show that the operation properties based on the established mathematical model coincide with that of a practical SCR shaft generator, which is to say that the established mathematical model of power supply control processes of marine SCR shaft generator established is reasonable. ©2009 IEEE.