Recently in electronic and automobile industry, polymer materials were selected to replace metals in many products because of miniaturization and weight reduction. So the weld between polymers and metals became very important. Currently, the ways were limited to adhesive joint or the mechanical weld which both had obvious defects. In this paper, the direct-welding methods were studied and the welds based on compress-molding were viable and useful. The welding strength enhanced because the reaction between polymers and modified metals were confirmed.