Abstract: A control method based on motion description language (MDL) is proposed, to reduce requirement for network bandwidth and to distribute reasonably computational and communication resources in tele-robotic systems. The open-loop and closed-loop parameters in motion primitives are derived based on orthogonal decomposition of robot trajectory, by which the expressiveness of MDL is guaranteed, and four kinds of motion primitives are constructed for the tele-grasping task. A network-based tele-robotic system is constructed, in which the Phantom Omni is used as the master device and the Motoman 6-DOF industrial robot as the slave system. Experiments are conducted to compare the direct control method and the MDL-based control method, and experimental results demonstrate the feasibility and efficiency of the proposed method.