Aluminum alloy was a material widely used in the fields of engineering but not easily connected by welding
process. In this research experiments conducted using friction stir welding (FSW). This study aims to analyze the resulting mechanical properties as well as studying the effect of welding parameters i.e. shoulder diameter, round tool, and speed in welding (feeding) in the friction stir welding on aluminum material AA 5052. The mechanical properties was analyzed include tensile strength and bending strength of results welding. Best mechanical properties are on the tool with a shoulder diameter of 17.8 mm the highest tensile strength at 1300 rpm with a feeding rounds of 50 mm/min at 222.1 MPa and the highest of bending strength at 1300 rpm with a feeding round 208 mm/min at 422.6 MPa, With a smaller shoulder
diameter, round and proper feeding friction and forging processes that occur while welding gives smaller influence on the decline in good mechanical properties in the material to be joined.