Friction Stir Welding is a type of Solid State Welding (SSW) welding where FSW welding utilizes friction that occurs between the tool and the workpiece to be connected without reaching the melting point of the object to be welded, this welding is very suitable for connecting polymeric materials such as HDPE (high density polyethylene). HDPE material has strong properties material that has code no. 2 is good for food and medicine, even though it is recommended to use HDPE only once, the purpose of this study is to find out the results of the macro structure test, dance test and bending test on welding of FSW double-sided HDPE material and reducing the bending / distortion that occurs after welding. This study uses HDPE sheets with dimensions of 5mm thickness, width 80 cm, length 100 cm. Welding is carried out with a rotational speed of 900,1500 and 2000 rpm, with a welding speed of 5 mm / minute dept of pluge 0.5 mm made all the same during the welding process, three tests conducted in this study are testing the tensile strength and bending macro structure of the welding results. The results of this study after mechanical testing the results of bending and macro structure tests showed the best results were the variation of the tool rotation of 900 rpm with a tensile strength of 18.8 Mpa with a strain value of 8.7% while the stress on the raw material was 23.9 Mpa and a strain of 25% and a variation 2,000 rpm which gets the best results among all variations. In the bending test results into two tests with the face and root because welding is done on both sides the results obtained in the 2000 rpm root variation section the average results obtained are 18.9 Mpa and 900 rpm face results with an average of 21.95 Mpa.