The invention provides an engine air cylinder sleeve, and belongs to the technical field of cars. The engine air cylinder sleeve solves the problems that an existing air cylinder sleeve is large in expansion and contraction quantity, a cylinder mat is difficult to seal, the weight is large, and fuel economy is influenced. The engine air cylinder sleeve is cylindrical, the inner side wall of the air cylinder sleeve is a cylindrical face, the outer side wall of the air cylinder sleeve is a rotary curve face formed by rotation around the axis of the inner side wall, a wall thickness part is formed between the cylindrical face and the rotary curve face, the thickness of the wall thickness part is decreased from top to bottom. By means of the engine air cylinder sleeve, the cylinder sleeve weight can be reduced, and meanwhile, the cylinder sleeve expansion and contraction quantity can be reduced.