Building and implementing a multimedia bodybuilding platform based on a traditional treadmill with virtual reality, sensor technology, motor control technology and the virtual human technique. This paper introduces the method of generating largescale 3Dscenes, the technique of rendering 3Dscenes by OSG（Open Scene Graph）, and emphases on designing and implementing the virtual human motion algorithm.Finally,it reaches the dynamic interaction among the users ，the virtual scene and the virtual humans, and makes the users immerse in the scene.