The excavator usually needs to use linear excavation when excavating trenches and leveling slopes， and it requires a high-precision operation. This paper proposes a multi-joint motion planning and control strategy to realize high-precision linear mining operations. Firstly， the kinematic model of the excavator working device was established， the kinematic trajectory of each joint was obtained by inverse kinematic solution according to the linear motion trajectory of the bucket tooth tip， and the target angle of the boom was planned again according to the predicted angle of stick and bucket. The dynamic model parameters of each joint of the excavator online were identified by using recursive least squares， and the variation of joint angle in the delay time was predicted in real time to compensate for the tracking control errors caused by the system delay characteristics. Finally， the existing excavator was transformed into an intelligent excavator and the working device model of AMESim was built. The hydraulic system model parameters and excavator models are modified based on experimental data， and the control model is established in Simulink and the excavator model of AMESim is co-simulated to verify the reliability of the control algorithm. The simulation results show that， compared with the traditional PID control strategy， the strategy based on joint cooperative control has better performance in the trajectory control of linear excavating buckets.