The invention discloses a closestool shell mold which comprises an inner mold body and an outer mold body. The middle of the outer mold body is concaved, the outer mold body is in a bucket shape, no seal cover is arranged on the upper portion of the outer mold body, the upper portion of the inner wall of the outer mold body is wider than the lower portion of the inner wall, the center of the bottom of the inner wall of the outer mold body protrudes to form a protrusion, a plurality of communicated grooves are formed in the bottom of the inner wall of the outer mold body, and a water outlet hole is formed in one groove and provided with a semipermeable membrane. The upper portion of the inner mold body is wider than the lower portion of the inner mold body, the center of the bottom of the outer wall of the inner mold body is concaved to form a concave portion, and an air channel is arranged in the inner mold body and provided with an air inlet and an air outlet. The closestool shell mold is simple in structure and convenient to mount and dismount.