Abstract: Aiming at the trajectory tracking error caused by the low trajectory accuracy of industrial robots, the responses of dynamic cutting thickness and time delay during cutting to the trajectory tracking error are analyzed. Taking the increase in process damping of the bottom caused by trajectory tracking error into consideration, a dynamic cutting force model including the trajectory error is developed. The model is verified by milling experiments, and it is found that the change of dynamic cutting thickness, the time delay effect, and the increase in process damping caused by the trajectory tracking error of the robot, can increase the critical axial depth of cutting and improve the stability range of milling, and will decrease the surface quality and dimensional accuracy. The proposed theoretical model explains the special phenomenon that the chatter occurs and then disappears in the robot milling experiment, can serve as a theoretical model for improving the robotic milling efficiency and suppress the milling chatter.