Changing on virtual human joint moments in simulation is significantly meaningful to analyz the productions maintainability. For some maintenance work it requires slow operations, and the simulation process can be viewed as a sequence of static postures. Changes of joint moments during the whole process can be observed by computing each static posture joint moments. Taking the example of armor vehicle maintenance task, binding static human force model to simulation process, the design and implement of computing human joint moments online based on Jack platform are introduced, and the feasibility of human work postures is online evaluated by adopting the guideline of NIOSH81.