The invention discloses a sealing pump for a plunger pump and the plunger pump. The sealing device comprises a pump cylinder body, a plunger part, a stuffing box, a pressing cover, a dust-proof sealing piece and an anti-abrasion sealing piece, wherein a plunger hole is formed in the pump cylinder body; one end of the plunger part stretches into the plunger hole; the stuffing box is in a cylindrical shape, one end of the stuffing box stretches into a sealing cavity, and the other end of the stuffing box is arranged outside the sealing cavity; the sealing cavity is an annular cavity which is formed between opposite circumferential surfaces of the plunger part and the plunger hole; one end, which stretches into the sealing cavity, of the stuffing box is provided with an annular flange; the outer circumferential surface of the stuffing box is in clearance fit with the inner circumferential surface of the plunger hole; a stuffing cavity is formed in space among the end surface, which faces the outer part of the plunger pump, of the annular flange, the inner circumferential surface of the stuffing box and the outer circumferential surface of the plunger part, and a sealing piece is arranged in the stuffing cavity and is pressed by the pressing cover; a sealing ring is arranged between opposite surfaces of the stuffing box and the pump cylinder body. According to the sealing device for the plunger pump, disclosed by the invention, sealing can be ensured, the sealing piece can be conveniently taken out, and a function of preventing dust in air from entering the sealing surface is obtained. The invention also discloses the plunger pump which is provided with the sealing device.