This book mainly deals with the cognition of the hydraulic transmission system, the assembly and disassembly of hydraulic components, diagnosis and maintenance of malfunctions in the fundamental hydraulic circuit, diagnosis and maintenance of malfunctions in the hydraulic transmission system, assembly and disassembly of pneumatic components, diagnosis and maintenance of malfunctions in the pneumatic transmission system, etc. It can be used as a textbook for majors of maintenance and management of the electromechanical equipment, electromechanical integration, repair and driving of the high-speed trains, rolling stock, numerical control technology, mould design and manufacturing, mechanical manufacturing and automation, etc. in vocational colleges, and as a professional training material for related disciplines by vocational schools.