提出了一种圆环三角法进行尺寸稳定性评价，通过圆环三角试样沿底边开口后引起的顶角及两侧面平行度的变化对7050铝合金的尺寸稳定性进行了评价。并将深冷处理与7050铝合金的固溶时效进行结合，探索了不同工艺对7050铝合金圆环三角尺寸稳定性的影响。结果表明：淬火态圆环三角试样开口顶角角度和平行度变化最大，而固溶处理后时效处理前增加深冷处理圆环三角试样顶角角度和平行度变化最小。尺寸稳定性的变化结果与残余应力检测结果吻合，说明该方法能够从残余应力层面对尺寸稳定性进行有效评价。

A ring triangle method was proposed to evaluate the dimensional stability. The dimensional stability of 7050 aluminum alloy was evaluated by the change of vertex angle and parallelism of two sides after opening of the ring triangle specimen along the bottom line. The cryogenic treatment and solution aging of 7050 aluminum alloy were combined to explore the influence of different processes on the dimensional stability of 7050 aluminum alloy ring triangle. The results show that the change of vertex angle and parallelism in quenched ring triangular specimen was the largest, while the change of vertex angle and parallelism which in specimen treated by conduction of cryogenic treatment after solution and prior to aging was the smallest. The results of dimensional stability was in good agreement with the result of residual stress, which show that the ring triangle specimen method can effectively evaluate the dimension stability from the residual stress layer.