Temperature is the key factor in the accuracy of residual stress test by ultrasonic. The effects of temperature on the base metal,the heat affected zone and the weld of A7 N01 P-T4 aluminum alloy welded joints were studied in environment lab,and then the temperature modified model was established in this paper. The results showed that when the temperature was at lower temperature（0,3,8 ℃）,the temperature played the leading role in the effect on acoustoelastic effect,but the relationship between acoustoelastic effect and temperature had nothing to do with the testing materials. When the temperature raised,the elastic modulus E and density ρ changed obviously. When the modified temperature was at 2,3,8 ℃,the temperature modified model was Δσ =K [t-（0.414 05 T-0.874 06）].