To ensure the construction safety of arch bridge in the process of cantilever casting and to ensure that the force conditions of the arch ring of the completed bridge could meet the ra‐tional state requirements ,the New Midi Bridge (a reinforced concrete box and open spandrel deck arch bridge with a main span of 189 .9 m) in Panzhihua City ,Sichuan Province was cited as an ex‐ample .The first‐order optimization method of the finite element software ANSYS was used to study the optimization of the fastening stay forces for the bridge in tw o steps of the construction optimization and completed bridge optimization and the ANSYS was also used to build up the pa‐rameter model of the bridge .In the construction optimization ,the global stress of the arch ring was taken as the target function and the optimization calculation of the fastening stay forces in the process of the cantilever casting was implemented .In the completed bridge optimization ,the ben‐ding moment and eccentric distances were respectively taken as the target functions ,the influences of live load effect were considered and the fastening stay forces at the time of the longest cantilever were globally adjusted .The results of the study show that in the cantilever casting ,the tensile stress levels of the optimized arch ring obviously decrease and the construction safety of the arch ring in the cantilever casting is ensured . T he force conditions of the arch ring of the completed bridge are effectively improved ,w hich ensures that the force conditions of the bridge to be more rational at the operation stage .%为保证拱桥悬臂浇筑过程中的施工安全以及成桥后拱圈受力满足合理状态要求，以四川攀枝花新密地大桥（主跨为189．9 m的上承式钢筋混凝土箱形空腹式拱桥）为工程背景，采用ANSYS一阶优化方法，分施工优化和成桥优化2步对其扣索索力进行优化研究。利用ANSYS有限元软件建立该桥参数化模型，施工优化中以拱圈整体应力为目标函数，对施工过程中的扣索索力进行优化计算；成桥优化中分别以弯矩和偏心距为目标函数，并考虑活载效应的影响，对最大悬臂状态时的扣索索力进行整体调整。结果表明，优化后悬臂浇筑过程中拱圈的拉应力水平明显降低，保证了悬臂浇筑过程中拱圈的施工安全；成桥后的拱圈受力情况得到有效改善，使运营阶段的拱桥受力更为合理。
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