Abstract: This paper pesents a robot grasping planning system based on the hierarchical reasoning—KBGS.The system divides the object knowledge into two levels:coarse knowledge and fine knowledge.First the KBGS carries out the grasping scheme planning on the basis of the coarse knowledge,the planning result is a symbolic grasping scheme for the environment and task.Then based on this scheme,fine grasping parameters are reasoned using the fine knowledge of objects.