The invention discloses a device and method for treating offshore oil pollutants. The device comprises a boat body, wherein a power box is fixedly connected to the left side of the boat body, a motoris fixedly connected to the rear side of the bottom of the inner wall of the power box, a driving wheel is fixedly connected to the output end of the motor, a bearing is fixedly connected to the frontside of the bottom of the inner wall of the power box, and a bearing column is fixedly connected to an inner ring of the bearing. By cooperatively using the boat body, the power box, the motor, the driving wheel, the bearing, the bearing column, an auxiliary driving wheel, a belt, a connecting column, a sliding plate, a groove, a positioning plate, a limiting plate, a positioning groove, a connecting plate, a sliding sleeve, a sliding rod, a support, a positioning block, a water tank, a filter plate, an oil outlet, a water outlet, a water pump and a water pipe, the problem is solved that an existing treating device is lower in working efficiency, accordingly workers need to repeatedly treat oil pollutants, and the labor amount of the workers is increased.