The processing of the cylinder bores is one of the important processes of cylinder processing,its processing quality determine the quality of the engine directly.By analyzing the structure of a car engine cylinder,cylinder bore machining precision requirements and manufacture difficulties,cylinder production line mode and cylinder bore processing equipment were determined.The design of the special machine overall scheme,special fixture structure,transmission system,the structure of tool system and the structures of the bed and the column were focused on.The special machine successful development and putting into operation provide valuable experience for future research and development of similar machine.