The invention discloses a hyperbolic function sliding-mode control-based chaotic oscillation suppression method of a power system. The chaotic oscillation suppression method is implemented according to the following steps of 1, calculating a relative error e(t) according to a relative rotor angle actual value x<1>(t) and a relative rotor angular speed ideal value x(t) of a second-order interconnection dual-motor power system; 2, setting a sliding-mode controller parameter; 3, calculating a motion state of a system sliding-mode surface according to the relative error e(t) and the sliding-mode controller parameter; and 4, generating a controller output u(t) by joint efforts of the sliding-mode controller parameter and a motion state equation, making the controller output acted on a rotor of a power generator, outputting the current relative rotor angle actual value x<1>(t), forwarding to the step 1, and adjusting the controller output according to the relative error. According to the hyperbolic function sliding-mode control-based chaotic oscillation suppression method of the power system, a chaotic oscillation phenomenon generated in the interconnection dual-motor power system is rapidly and effectively suppressed by the sliding-mode controller of a hyperbolic tangent function.