Electrification is a current research hotspot in construction machinery and has been exploratory applied in small-sized excavators. There are few research reports on the electrification of medium and large-sized excavators with higher cost-effectiveness. In this thesis, based on the electro-hydraulic drive tooling structure which is more suitable for the operating condition of medium-sized excavator, cubic polynomial is used to fit the trajectory of excavator in sections. The D-H parameter method is used to study the relationship between operating condition, tooling attitude of medium-sized excavator and the pressure and flow rate of driving cylinder, and the whole machine model of medium-sized electric hydraulic drive excavator is established. Through simulation studies and experimental validation on a 37 t prototype, the discussion explored the motion laws of the tool under the constraints of the expected working trajectory, offering a reference for the design selection and trajectory control of the electric hydraulic drive system for medium-sized excavators.