The Friction Stir Welding (FSW) has mainly been used for making butt joints in Al alloys. Development of FSW would expand the number of applications. The FSW is a relatively solid-state joining process. This study possibility of a welding between C1020 and Al6063 by means of FSW has fundamentally clarified. The primary process parameters, such as a rotating speed, rotating direction of tool and off-set of pin periphery from materials interface were optimize, respectively.