The present invention relates to a generator set rectifier device, which comprises a fully-controlled rectifier circuit, and controllers. The fully-controlled rectifier circuit is used for converting the output AC of a generator set into a DC. The controllers are composed of a DC voltage controller and a variable speed controller. The DC voltage controller is used for acquiring the AC voltage value and the AC current value at the input end of the fully-controlled rectifier circuit and the DC voltage value and the DC current value at the output end of the fully-controlled rectifier circuit, and then generating a first control signal for controlling the output DC voltage of the fully-controlled rectifier circuit based on the acquired voltage values and current values. The variable speed controller is used for generating a second control signal for controlling the rotating speed of the generator set based on the DC voltage value and the DC current value. According to the technical scheme of the invention, the DC power generation function for the variable-speed generator set with the fully-controlled rectifier is realized. Meanwhile, the device is fast in response speed and stable in dynamic performance. The above device can be applied to conventional generator sets. Moreover, the commutation problem of large-capacity DC generator sets can be solved.