The purpose of this study is to investigate the effects of process parameters on the joint characteristics of advanced high-strength steel DP780 and Al5052 alloy sheet in mechanical clinching process. The defects in the clinching joint, such as necking of the upper sheet, cracks in the lower sheet, and no interlocking, occur because of the different ductility between advanced high-strength steel and aluminum alloy. In this study, the effect of the process parameters of the clinching process on the joinability of advanced high-strength steel with Al5052 alloy was investigated using finite element (FE) analysis. From the result, the die radius, die depth, and die groove shape were mainly affected by the joinability of advanced high-strength steel with Al5052 alloy. H-type tension test was performed under the same condition as the FE analysis. In addition, the joint strength was determined by interlocking length as well as neck thickness.