In this study, to reduce the weight of cross member assembly for small truck. In order to optimize the design of the cross member structure by changing the equation into the rivet coupling method, The size and the hole spacing of the large sheet plate, the rivet hole size of the large sheet plate, In the structural analysis, we looked at what was going to happen, and the tensile, shear The load test was carried out to investigate the damage caused by the maximum load acting on the rivet. Riveting work, but to improve productivity, we developed automated riveting device using robot To reduce the number of workers, reduce jig transfer and installation time, and reduce load factor. To produce the maximum output of the product.