The invention discloses a method for controlling a PMSM (permanent magnet synchronous motor) servo system based on friction and disturbance compensation. In the method, a feedforward compensation method based on a friction model is combined with an auto disturbance rejection technology and the feedforward compensation method is complementary with the auto disturbance rejection technology mutually. In the method, a Stribeck friction model is utilized to carry out modeling on system frictions, a GA (genetic algorithm) is adopted to carry out offline identification on parameters, and an estimated value generated by an identification model carries out feedforward compensation; a state observer in the auto disturbance rejection technology observes and compensates overcompensation or undercompensation of the frictions as well as nondeterminacy and external disturbance caused by modeling errors in the system; and finally a differential tracker and a nonlinear control law are used to arrange a transient process for fixed position signals, thus solving the conflict between rapidity and overstrike and ensuring stability of the system and finite time convergence. By using the combined control, the compensation capacity of the system for the frictional nonlinearity can be improved effectively, the low-speed performance of the system is improved, and the tracking accuracy and the anti-disturbance capacity of the system are enhanced.