The invention relates to an electric propulsion converter device for an ocean fishing boat, and in particular relates to an electric propulsion converter for an ocean fishing boat. The electric propulsion converter comprises a cabinet; a power unit, a control unit, a cooling unit and wiring harnesses are arranged in the cabinet; the power unit comprises a rectifier module, an inverter chopper module and a direct-current support capacitor; the rectifier module comprises a rectifier input copper bar, a rectifier power module and a main contactor; the inverter chopper module comprises a three-phase inverter output copper bar and an inverter chopper power module; the control unit comprises a traction control unit, a sensor, a filter and a power supply; the cooling unit comprises a heat exchanger, a water pump, a water replenishing box, a pipeline, a temperature sensor, a pressure sensor, a valve and a cooling pipeline; and the wiring harnesses include low-voltage wiring harness and high-voltage wiring harness. Electric transmission based on the converter gradually replaces the traditional transmission mode by the advantages, such as low speed, large toque, uniform low-speed operation, flexible configuration and high reliability; the electric transmission is the mainstream development direction of ship propulsion; and thus, the electric propulsion converter has wide application prospect.