本文借助《起静定刚架的影响线函数》的原理，准确地画出结构在活载作用下的影响线，确定最不利的荷载位置，在此基础上提出一种比较合理的城市立交桥的结构——框架结构。 In this paper, with the help of the principle of “influence line function of static frame”, the influence line of structure under live load is accurately drawn and the most unfavorable load position is determined. On this basis, a reasonable urban overpass Structure - Frame structure.