In combination with the characteristics of Daheiting Power Station whose unit feedback chain is rather long, a technology of double PID was put forward and applied. Proved by simulation, test and operational practice, the technology can make the parameters of effective static stability, 3- minute idling swing, static time of servomotor, frequencies of wave crest of 100% load rejection and over 3% rated rotational speed ect., better than international standard and improve the quality of governor adjustment.