Abstract Three-phase short-circuit of pumping station of synchronous machines have serious influencetoward the machines and electric power systems. In designing of the systems, Protect of short-circuit mustaccording to design of electric current. Analytic means of theory not only complex but also confined. Amathematical model of three phase synchronous machines is developed in this paper. Based on this model,three-phase short-circuit of synchronous machines are emulated and computed .Two kinds of method ofcalculation are compared. Emulation have characteristic of briefness and higher precision.