Common excavator structures include power units, working devices, slewing mechanisms, operating mechanisms, transmission mechanisms, walking mechanisms and auxiliary facilities.

From the appearance, the excavator consists of three parts: the working device, the upper turntable and the traveling mechanism. According to its structure and use, it can be divided into: crawler type, tire type, walking type, full hydraulic, semi-hydraulic, full rotation, non-full rotation, general type, special type, articulated type, telescopic boom type and other types.

The working device is the device that directly completes the excavation task. It is hinged by three parts: boom, stick and bucket. Boom lift, stick extension and bucket rotation are controlled by reciprocating double-acting hydraulic cylinders. In order to meet the needs of various construction operations, the excavator can be equipped with a variety of working devices, such as digging, lifting, loading, leveling, clamps, bulldozing, impact hammers and other working tools.

The slewing and traveling device is the body of the hydraulic excavator, and the upper part of the turntable is provided with a power device and a transmission system. The engine is the power source of the excavator, most of which use diesel oil in a convenient site, or an electric motor can be used instead.

The transmission mechanism transmits the power of the engine to the hydraulic motor, hydraulic cylinder and other actuators through the hydraulic pump, and pushes the working device to move, thereby completing various operations.