From the point of medium quality, conduction quality and interaction quality, this paper points out the design viewpoint of three - dimensional system of quality of service, displays the principle of three - dimensional system of quality of service. Based on the analysis above, this paper sets up a structural equation model on the quality of service design of China Certification Center Inc. By analyzing the mutual - effect of the latent variable, the scoring and influence efficient of structural variable and observable variable in the structural equation model, this paper brings forth the primary design scheme of the quality of service of China Certification Center Inc.