In this paper, the effect of different workpiece geometries on the properties of welded Al-7075-T6 parts in rotational friction welding process has been investigated by using experimental and finite element approaches. Welding process is continuous drive friction welding. In this research, the samples diameter were selected equal to 25 mm and the samples length were selected equal to 75 mm. The process variables such as friction time (t1), forging time (t2), friction pressure (P1) and forging pressure (P2) where assumed to be constant, whereas, rotational speeds were variable and selected equal to 2000 rpm and 2500 rpm. Three cylindrical parts with different cross sectional geometries were adopted as three samples. Finally, to verify the accuracy of numerical analysis, the experimental and thermo-mechanical simulation results were compared and found a good agreement between them. Since, an experimental test is a time consuming and a costly process activity, it was decided to get more results by using an alternative method such as finite element simulation technique. Results of this study showed that changing in front geometric of workpiece is an effective factor for tensile strength, length of workpiece and generated flash in welded area and by changing this factor, properties of welded area can be improved.