The utility model discloses an electrolysis device for treating domestic sewage of an offshore platform. The electrolysis device comprises a buffer unit, a self-cleaning filter, an electrolysis electrode, an electrolysis reaction tank, a discharge tank and a PLC monitoring unit, The buffer unit comprises a tank body and a self-circulation crushing pump, and the tank body is divided into a first-stage partition tank and a second-stage partition tank; A crushing and conveying pump is connected between the self-cleaning filter and the second-stage partition tank; a blow-down valve of the self-cleaning filter is connected to the second-stage partition tank; And an outlet pipe of the self-cleaning filter is connected with the electrolytic electrode, the electrolytic reaction tank and the discharge tank, the discharge tank is connected with the output pump and the discharge pump, and the output pump is connected with the spray head for cleaning the screen. The sewage treatment process provided by the utility model solves the problem of sewage blockage in the traditional process, and can be well applied to offshore platforms, such as oil and gas drilling platforms or ships.