The invention discloses a paper stock pump which is provided with a pump shaft, a rear protecting plate, a front protecting plate and an impeller. The impeller is composed of a hub, a blade base plate and blades. The front end of the hub is fixedly connected with the blade base plate in a perpendicular mode. The blades are circumferentially arranged on the blade base plate in an array mode. The rear half portions of the blades are fixedly connected with the blade base plate. The outer end of the blade base plate corresponds to the inner wall of the rear protecting plate and is in clearance fit with the inner wall of the rear protecting plate, and the clearance between the outer end of the blade base plate and the inner wall of the rear protecting plate is 1.6 mm. The lower ends of the front half portions of the blades are in clearance fit with the rear protecting plate, and the clearances between the lower ends of the front half portions of the blades and the rear protecting plate are 1.2 mm. The upper ends of the blades are in clearance fit with the front protecting plate, and the clearances between the upper ends of the blades and the front protecting plate are 1.2 mm. By the adoption of the structure, the paper stock pump has the advantages of being novel in structure, high in blockage preventing capacity, conveying performance and anti-cavitation capacity and the like.