The invention relates to a generator wide area damping control method based on a model-free adaptive control algorithm and belongs to the electric power system stabilization analysis technology field. The method comprises steps that control parameters of a traditional generating wide area damping control method are acquired according to a traditional transfer function expression and a parameter calculating formula; control parameter initial values of the generator wide area damping adaptive control method is calculated according to the acquired control parameters of the traditional generating wide area damping control method, an acquired pseudo gradient vector initial value is taken as an initial point, and an estimated value of a pseudo gradient vector is updated online by utilizing input output data actually measured by a controlled system; a generator wide area damping adaptive control signal is calculated according to the estimated value of the pseudo gradient vector which is updated online; repeated calculation is carried out till the generator wide area damping control signals reach to a maximum level. The method can guarantee a control effect of generator wide area damping control under multiple operation states of the system.