Offshore Oil Filter is installed under the drilling platform to filter crude oil mixed with seawater. A sponge with oil absorption but no water absorption is used inside and can be reused. The oil-water separation membrane is paved below, which has high durability and can achieve more than 98% of the oil-water separation effect. Wave energy to drive the generator to generate electricity, so that the internal motor of the product is rotated and the filtered crude oil is extracted for use.