In cascaded H-Bridge (CHB) multi-stage active rectifier, a novel double model predictive control (MPC) method is proposed to solve the problems of PI controller which is difficult to accurately adjust and response is not fast enough.The first model is to discretize the mathematical model of CHB multi-stage active rectifier, then predict the sampling data by using the discretization formula, and finally control the objective function by the difference between the predicted value and the reference value. The secondary model uses the power conservation method to calculate the reference source current, eliminating the outer loop regulation based on PI control. In addition, a luenberger-based observer is used to estimate the DC load current, thus reducing the number of sensors. Finally, the simulation experiment of single-phase 7-level CHB active rectifier with MATLAB/Simulink verifies the validity of this method under steady and transient conditions.