This paper uses a rear sub-frame as the mother model and uses Reverse engineering technology to measure the rear sub-frame point cloud through ATOS non-contact scanners. Then, the point cloud‘s data processing is completed in Imageware. Finally, the point cloud is imported into UG NX4.0 software, after a series of surface cutting, chamfer suturing and sheet thickening; the sub-frame’s three-dimensional model is established. Besides, we complete the static finite element analysis and modal analysis of the sub-frame’s three-dimensional model through the ANSYS software. The results of analysis support theoretical basis for the structural improvement of sub-frame.