The invention relates to an overpass which is a three-layer overpass with two bridge surfaces at a crossroad. The first-layer ground of the overpass is not provided with lanes. And only pedestrians can pass. The second-layer bridge surface of the flyover is rectangular. The four right-turning lanes, the two north-south straight lanes and the four U-turn lanes are arranged on the second-layer bridge floor in the whole course, and the front half parts of the four left-turning lanes are arranged on the second-layer bridge floor. And the three layers of bridge surfaces of the flyover are cross-shaped. And the two east-west straight lanes are arranged on the three-layer bridge floor. And the rear half parts of the four left turning lanes are arranged on the third-layer bridge floor. The flyover is provided with three skylights. The twelfth lane passes through the first skylight. The ninth and tenth lanes pass through the second skylight. And the No.11 lane passes through the No.3 skylight. Six lanes in the north-south direction are arranged on the second-layer bridge floor of the overpass, the six lanes are the lanes 12, 2, 10, 9, 1 and 11, six lanes in the east-west direction are arranged on the third-layer bridge floor of the overpass, and the six lanes are the lanes 12, 3, 10, 9, 4 and 11.

本发明所述立交桥，为十字路口两个桥面三层立交桥。立交桥的一层地面未设置车道。仅供行人通行。立交桥的二层桥面是长方形。四条右拐弯车道、两条南北向直行车道、四条调头车道全程在二层桥面，四条左拐弯车道的前半部分设置在二层桥面上。立交桥的三层桥面呈十字形状。两条东西向直行车道设置在三层桥面上。四条左拐弯车道的后半部分设置在三层桥面上。立交桥有三个天窗。12号车道经由①号天窗。9、10号车道经由②号天窗。11号车道经由③号天窗。立交桥的二层桥面上有六条南北走向车道，六条车道是：12、2、10、9、1、11号车道，立交桥的三层桥面上有六条东西走向车道，六条车道是：12、3、10、9、4、11号车道。