Abstract: Generally, the front sub-frame has two positioning holes and two through holes.During vehicle assembly, the front sub-frame is positioned on the tooling first, then aligned with the threaded holes of the body along with the tooling.Next, the two positioning holes of the front sub-frame are secured to the body through bolts, and finally, the two through holes of the front sub-frame are fastened to the body through bolts, completing the assembly of the front sub-frame.This type of front sub-frame and body adopt a self-positioning structure, which uses the clamping force of bolts to secure the sub-frame to the body.Since the front sub-frame supports components such as the engine, gearbox, suspension, etc.,it bears a large load.During sudden acceleration or deceleration of the vehicle, the front sub-frame will slide, causing noise.To solve this problem, this paper designs a new type of front sub-frame positioning structure and analyzes it through VSA simulation to provide relevant dimensions and tolerances to ensure that the sub-frame can be assembled normally.