Friction stir welding is a novel, economical and high quality technique among aluminum welding and joining methods. In this present paper, by introducing the friction stir welding the affecting parameters on thermal, micro structural and mechanical properties of 7000 series aluminum aerospace alloys joining using Friction Stir Welding is investigated. Results show that the sizes of nugget grains are between 5 through 12 micrometer and the least grain size constructed in nugget zone which the thermal effect is responsible for. By using thermal analysis and experimental results, the amount of loosed energy during FSW process can be drawn. Furthermore the effect of process parameters on loosed energy can be investigated. In this work and in the beginning and during welding, the appropriate temperature near to the tool shoulder is 330 degrees centigrade which can be used as a norm for quality control of weld ability. Cylindrical tool with plain pine surface made a welding joint with strength up to 80 percent of base metal. Welding quality is strongly affected by defects in joining zone which came from selecting non proper welding parameters.