In the current situation where the height restrictions on aviation are becoming increasingly strict, the design of long-span bridges confronts the twin challenges of bridge type selection and structural optimization. Against the backdrop of a cross-river bridge with a main span ranging from 400 m to 465 m and the height restriction 60 m on aviation, the applicability of the low-pylon cable-stayed bridge, the steel truss continuous beam bridge and the self-anchored suspension cable - stayed collaborative system is systematically analyzed. The findings indicate that through the innovative design of a V-shaped pylon, the pylon height of the low-pylon cable-stayed bridge can be optimized to 35 m. The application of side-pier counterweight and pre-lowering jacking techniques for the steel truss continuous beam bridge can solve the problems such as negative reaction forces resulting from a small side-span ratio and internal forces during long-cantilever construction. As for the self-anchored suspension cable - stayed collaborative system, by means of steel pylon design and optimization of cable force distribution in the combined zone, the internal forces of the main pylon and main girder are remarkably decreased. The research outcomes offer a scientific foundation for the selection of long-span bridge under the condition of height restrictions.