Abstract: A skeleton modeling method for virtual human is presented based on multi-rigid-body system theory. It can efficiently overcome the limitations of the DH-notation which is only applicable to serial open chains. First, a simplified virtual human model with 16 joints & 39 DOFs is proposed. This is based on reasonable reduction and assumption on both motion joints and DOFs, and only those key joints and DOFs which can mostly express the low-frequency characteristic of human motion are kept. Then the virtual human model is abstracted as a multi-rigid-body system whose limbs and trunk are coupled with mechanical revolute joints. This can be done once the anatomical characteristic of joints and bones is ignored. Finally the multi-body tree model and lower body array are introduced to represent the skeleton structure of the virtual human. The simulation results show that our model could naturally exhibit the complex branch feature of virtual human and could easily realize arbitrary resolution extension for the human model. Besides, recursive computation can also be achieved easily.