The invention relates to the field of water pump bodies and particularly relates to a water pump body casting for an engine. The water pump body casting comprises a bearing tank, a positioning component and a mold shell, wherein the bearing tank is vertically arranged in the bearing tank and is provided with an accommodating cavity for placing the mold shell, the mold shell is placed in the accommodating cavity, the positioning component is bridged on the bearing tank, and a liquid guiding block matched with the mold shell is arranged on the positioning component; and the mold shell comprisesa first mold shell and a second mold shell which are symmetrically arranged, a first pouring gate is arranged in the first shell, a second pouring gate is arranged in the second mold shell, the firstmold shell and the second mold shell are connected in a propping manner, and the first pouring gate and the second pouring gate are communicated to form the outline of a product. The water pump body casting has the beneficial effects that the structure is simple, and molten iron can be conveniently and rapidly poured into the first pouring gate and the second pouring gate.