Multi-stage treatment device for oil-water separation

The utility model provides a multi-stage treatment device for oil-water separation. The multi-stage treatment device comprises a first-stage treatment tank, a second-stage treatment tank and a connecting pipe, wherein the connecting pipe is arranged on the first-stage treatment tank and is connected with the second-stage treatment tank; wherein a pretreatment filter element assembly is mounted in the primary treatment tank; a fine treatment filter element assembly is mounted in the secondary treatment tank; a supporting structure for supporting the pretreatment filter element assembly is arranged in the primary treatment tank; a guide structure is arranged at the tail end of the liquid inlet pipe; a cylinder sleeve covering the outside of the fine treatment filter element assembly is mounted in the secondary treatment tank; and a secondary guide structure is arranged on the cylinder sleeve. Through the arrangement of the guide structure and the two-stage guide structure, the oilfield output liquid is guided a