Abstract: The algorithm is proposed for the case that the original input-output linearization method can only be used with pure resistance load, so that it can also be established with constant power load. In this algorithm, the nonlinear system obtained from the state space model of the converter is transformed into the linear system under the new coordinate system by the appropriate nonlinear coordinate transformation; then the controller is designed according to the classical linear control theory; finally, the output current is avoided from appearing in the calculation formula of duty cycle by the relationship between the output power, output voltage and output current of the boost PFC converter, which is successful to solve the problem of algorithm failure due to the change of output current is too large or discontinuous. The results of PSIM digital simulation showed that the algorithm has good dynamic and static characteristics. When different loads are connected, the response time is short, the output voltage is constant, and the input current accurately tracks the input voltage. When the load power changes, it also can achieve stable output current, and the current waveform is smooth, which shows that the algorithm has good robustness to the load.