The invention provides an excitation system control method applied to a black-start operating condition of a pumped storage unit, which is characterized in that a GCB non-voltage switching-on signal is sent out while a black-start process is started. According to the scheme of the invention, the GCB switching-on operation performed before a regulator enters the load state is subversively adjustedin the conventional black-start process, and the GCB non-voltage switching-on signal is sent out while the black-start process is started after the adjustment, thereby fundamentally solving the problem that the black start fails due to the fact that the GCB cannot be switched on in the same period, and improving the success rate of the black start.