A drain pump has a sealed cavity formed by a motor base and a pump casing. A partition plate divides the cavity into a motor cavity, and a pump impeller cavity. A side of the partition plate facing the motor cavity is provided with a bearing base. Another side facing the pump impeller cavity comprises a plane; a bearing mounted in the bearing base penetrates through the two cavities. The bearing in the pump impeller cavity slightly protrudes from the plane of the partition plate, and is tightly attached to a pump impeller in the pump impeller cavity, to form a second contact. The pump impeller and a pump impeller shaft are subjected to integral injection molding. The pump impeller shaft is tightly fixed in the bearing, penetrates through the partition plate, enters the motor cavity, and is connected with the pump shaft in the motor cavity.