Abstract:The designing principle and the overall structure of the destacking-robot were presented. Based on the modal analysis theory,the finite element model (FEM) of the robot was established by the finite element analysis software of COMSOL. Three typical pose of the robot were selected, and the natural frequency in each order was analyzed, to obtain the modal shape of it. The results show that the initial sixth order natural frequency of the robot under the there pose is centered from 15 Hz to 130 Hz. The small arm and big arm are the main influential factors of dynamic characteristic, which can be improved by suitably increasing the thickness of arm or increasing the rigidity of material. The natural frequency of overall robot is quite low, which can be improved through optimizing the parallelogram structure of arm to improve the rigidity of overall structure, and its vibration behavior is improved.