The aero-industry in union industry which includes a research development type, a knowledge accumulation type and a developed country type. The aero-industry of Korea is in semi-developed type stage but departed later than that of other country such as Taiwan, Indonesia etc. Therefore, the necessity of domestic airplane material is required. This study on 7050Al extruded alloy aims to suggest an adequate heat treatment conditions of T73, T74 and T76. The results of this study show that: 1. The optimum conditions of T7x heat treatment in extruded 7050Al alloy show this; T73 : 121℃×7hr+177℃×14hr T74 : 121℃×7hr+177℃×10hr T76 : 121℃×7hr+163℃×21hr 2. The 2nd step aging heat treatment such as T73, T74 and T76 etc. is effective in 7050Al alloy but the variation otf microstructure and mechanical property with dispersive inclusions produced for extrusion process causes some troubles. Accordingly, in order to produce a good 7050Al alloy, a careful attention is needed in manufacturing process.