Taking the working device of the hydraulic excavator as the research object, the theoretical models of kinematics and dynamics for the working device were established. The kinematics and dynamics simulation analyses for the working device were carried out by using the multibody mechanical system simulation software, the displacement and speed curve of the hinge point between the members were obtained,and the force change curves of the hinge point on each member were obtained. By analyzing the force change curve of the hinge points, the force change laws of each hinge point were obtained. It provides a theoretical basis for the design and research of the working device of the hydraulic excavator, and has practical significance for improving the working efficiency and reliability of the excavator.