A desirable amount of manufactured parts are made from sheet metal blanks. Parallel to developing tools and equipments, new methods in sheet metal forming are also inventing and completing. Amongst, hydroforming is a relatively new method that involves some advantages such as fewer costs and better formability. In this thesis a specific kind of hydroforming is studied. In this method gas pressure is used to stretch the metal sheet. The sheet metal is selected to be aluminum and the effect of elevated temperature is also studied. The design of manufactured die which used to performing tests, is presented. Test results are reported and finally some suggestions for further works in this field are given