The invention discloses an engine cooling water jacket. The engine cooling water jacket comprises a cylinder block water jacket body, a cylinder head gasket and a cylinder head water jacket body, wherein a water inlet is formed in the front end of the cylinder block water jacket body, water feeding holes are formed around each cylinder, the water feeding hole located at the rearmost end of each cylinder is a main water feeding hole, the cylinder head water jacket body corresponds to the cylinder block water jacket body, a water outlet is formed in the front end of the cylinder head water jacket body, water inlets corresponding to the water feeding holes in position are formed in the cylinder head water jacket body, and the water inlet located at the rearmost end of each cylinder is a main water inlet; the cylinder head gasket is arranged between the cylinder block water jacket body and the cylinder head water jacket body, a plurality of round holes are formed in the length direction of the cylinder head gasket, water passing holes are formed around each round hole, and each water passing hole located at the rearmost end is a main water passing hole; the water passing holes become larger gradually and sequentially from the front end to the rear end, and the size of each main water feeding hole is identical with that of the corresponding main water passing hole and that of the corresponding main water inlet. By the adoption of the engine cooling water jacket, the flowing speed of cooling liquid in the cylinder block water jacket body can be effectively increased, the temperatures of different parts of the cylinder block tend to be consistent, and the service life of an engine is prolonged.