Zhang's book Hydraulic Principle, Disassembly and Maintenance of Excavators was published by Chemical Industry Press in 2009. On the basis of introducing the working principle of hydraulic transmission system of excavator, the main structure, disassembly process, fault diagnosis and troubleshooting methods of key hydraulic components and systems such as hydraulic power component, hydraulic executive component, hydraulic control component, hydraulic auxiliary component and hydraulic transmission system are described in detail, and two typical excavators, CAT320C and Komatsu PCI 30-7, are analyzed.