Abstract: A P-transform matrix is applied to transforming the time-varying dynamic equations of a synchro generator into so-called P Park's equations, in result the state equations of one unit generator system are established. Owing to the nonlinear effect of the voltage regulator and the lagging of the a. c. exciter in an aircraft brushless a. c. generator, the forcing function of the main synchro generator UF（ t ） can be reduced to an exponential curve with a lagging tE and an equivalent time constant Tff.On the basis of the state equations above mentioned eight dynamic characteristics of the synchro generator are printed out separately on an electronic digital computer by four different methods: analysis; fourth-order Rungo-Ku-tta algorithm; exponential matrix （eAT）; and network topology. The computation accuracy and the stability region of these four methods are analyzed and their applicable range is established in conformity with their advantages. Then the following conclusions are drawn:1. The characteristic roots of the coefficient matrix at no-load sudden short circuit are the dynamic parameters of the synchro generator, i.e. Ta, Td", Tg", Td'.2. In symmetrical operation the synchro generator can be simplified as an one -order inertial link.3. The dynamic characteristics of the a. c. exciter （tE, Tff） have rather little effect on the maximum surge current of the synchro generator at sudden short circuit.4. In consideration of the non-linearity of the magnetic circuit in the synchro generator, it is verified that the inductor flux ψL and the capacitor charges qc are more suitable than iL and Uc to be taken as the state variables.