This paper investigated the dimensional variation problem of high defect rate of front wheel camber for Macpherson Sus-pension,found the factors affecting dimensional deviation and determined the contribution of each factor for the camber by contrasting the 3D dimensional tolerance simulation analysis results based on 3DCS with the physical assembly verification results,then solved the Mac-pherson suspension camber problem of high defect rate at last by optimizing those components tolerances with greater contributive factors and monitoring dimensional variation of these key factors in production at the same time.