This paper discusses the role of temperature and the width heating plate in the FSW jig on the strength of the aluminum alloy 1100 welded joint. FSW welding for aluminum alloy 1100 (AA 1100) material at this time has not yet produced optimal weld joint strength, so it necessary to study to improve the quality of the weld joint strength. The purpose of this study was to find the optimum strength of welded joints for aluminum alloy 1100 (AA 1100) with the FSW welding process. The process of determining the optimum value of the weld joint strength is carried out by varying the temperature of the heating plate and width of the heating plate contained in the FSW jig used. The method used in this study is an experimental method, the variation values used for temperature of the heating plate are: 175o C, 200o C, 250o C, and 300o C, and for the width of the heating plate, are: 10 mm, 20 mm, and 30 mm. To obtain data, tensile and impact test were carried out using standard specimen of ASTM E8-13a and ASTM E 23. The result of this study were the highest tensile strength and impact strength values were 62.64 M Pa and 0.5037 J/mm2 , respectively (58.66% and 75.19% of the strength of aluminum alloy 1100 without connection). These value were obtained from the combination of the temperature of heating plate is 250oC and a heating plate width is 10 mm.