The multi-variation characteristic of Hy-Vo silent chain was presented. The meshing design system with silent chain, sprocket and sprocket hob was built. The right meshing necessary condition of Hy-Vo silent chain and sprocket wheel was presented. It was indicated that the consistency of the chain pitch and the virtual side-center distance was the important base condition of the multi-variation when the Hy-Vo silent chain was tense. The interrelation of the enlaced circularity and tangency circularity were analyzed in the meshing design process. The practice showed that the multi-variation design method of the Hy-Vo silent chain was an important way to realize product innovation upgrade and intellectual property rights protection. This is the scientific and practical method. 