This book provides a large number of commonly used data, tables, inspection methods, inspection techniques and inspection cases for maintenance of CNC machine tools, focusing on Siemens 810T / M system and Fanuc 0C system, and also introduces Siemens 805 system and Siemens 804D system. Some inspection materials. In the PLC aspect, it mainly focuses on Siemens S5 system and Fanuc PMC-M, introduces the commonly used materials for CNC machine side fault inspection and inspection methods. Servo system introduces Siemens 6SC610, 6SC650, 611A and Fanuc a series of digital servo system connection, fault detection, fault inspection methods and fault inspection cases. In addition, it introduces the inspection of data lathes and digital grinding machines and the inspection of CNC machine reference points. This book has a clear structure, is easy to understand, has a lot of graphics and text, and has a wealth of diagnostic inspection cases, which reflects its practicality. This book can be used as a common tool for CNC machine maintenance personnel and as an introductory reference book for CNC machine maintenance personnel.