The present invention discloses a hierarchical control method for a cascaded rectifier. The method comprises the following steps of generating an initial parameter set for starting a cascaded rectifier system in an upper controller; transmitting the initial parameter set, by the upper controller, to respective bottom-layer controllers for controlling respective sub-modules in the cascaded rectifier system via a communication link; in each of the bottom-layer controllers: generating a PWM initial modulation signal based on the received initial parameter set and transmitting the PWM initial modulation signal as a control command to each sub-module in real time to start the cascaded rectifier system to work, and simultaneously acquiring the front-end input voltage and current and the back-endoutput voltage and current after each sub-module is started; and calculating a PWM real-time modulation signal by further control based on the values of the voltage and current detected in real time,and controlling the voltage input of the correspondingly connected sub-module by the PWM real-time modulation signal.