Casting structure design should accord with the requirement of machine equipment itself and mechanical processing technic requirements, still should accord with the requirement of casting process, casting structure design should pay attention to the following: 1.easy to make model, core box and moulding : 1) the appearance of the casting should strive to simple, in order to draw, should try to make the casting parting surface flat, and the smallest number; 2) casting lumen need to not use or less use cores when casting , when using core, should be easy to support, fix and exhaust out of the sand, when necessary, should have enough technology hole; 3) for the casting internal and external profile and strengthening rib structure, should be in the same direction with a certain structure of slope; 4) convex parts and casting on the casting body should not differ too much, take the same height, the same distance on the surface of the close several convex sets, best even into the whole convex part. 2.Reduce the tend of casting defects: 1) casting wall thickness should be uniform, in order to prevent the shrinkage, cracking, when need to ensure sequential solidification conditions, should try to make it in one direction change of wall thickness, when need to guarantee the solidification conditions at the same time, should try to make it with the thickness of broken walls; 2) casting wall and wall should be protected from sharp corners and connection between the metal concentration, thick wall and thin wall should be gradually transition, beware of mutation, so as not to cause heat and stress concentration, the formation of hot crack, shrinkage, etc; 3)partial thick section of casting should use hollow out or cast hole structure as far as possible,and appropriately strengthen rib reinforcement ; 4) the hole of casting plane wall, should use convex edge reinforcement in order to reduce the wall thickness; 5) when colling the casting structure ,it should shrink without resistance ; 6) try to avoid a large water level in the casting; 7) waterways, interlining cavity of large area in casting, such as gas path should have some connection column. 3.ensure the casting has good formability, control the minimum wall thickness of casting not less than allowable value.