In order to investigate the elevated-temperature mechanical behavior of aluminum alloy, tensile tests of domestic structural aluminum alloy 6082-T6，6N01-T6，6061-T4，6061-T6 under constant elevated temperatures were carried out, and their mechanical properties under various temperatures（20 ~ 300 ℃） were obtained, including the nominal yield strength, ultimate strength and elongation. It was found that the strain of aluminum alloy specimens at elevated temperature could hardly be accurately measured, leading that their elastic modulus was not obtained. The formulae of reduction factors on the mechanical properties of the 4 kinds of aluminum alloy at elevated temperatures were derived through numerical fitting method, laying a solid foundation of the research on fire resistance of aluminum alloy structures. Moreover, the theoretical formulae were compared with the reduction factors suggested by Eurocode and American Standard. The results revealed that the codes inclined to the safe side, and the American Standard was more conservative.