Nowadays, electronic equipments are using more widely specially at military equipment as the obvious effect on enhancing fighting strength of army. But the characters of complex structure, fuzzy technique and big cost among electronic equipment increase the difficulty of maintenance training. After the occurrence of virtual technique, virtual maintenance training becomes the newly way for maintenance training. In fact, virtual training of fault diagnosis is the important element of virtual maintenance training. So considering the characteristic that electronic equipment is hard to realize the maintenance training, a design scheme of fault diagnosis training based on virtual prototyping is presented. This scheme introduces the virtual prototyping model used for training and the related modeling method for three-dimension geometry model, planar graph model and information model at first. Then the basic logic and process of fault diagnosis training is defined. With the design of two different kinds of training modes, the training pertinence is clearer. So this scheme can be used to improve the ascendant skill.