The terrain conditions in the southwest mountainous area are complex. The design of bridges across river is influenced by many factors. Taking Qujiang Bridge as an example, the multiple schemes are compared and selected for the overall design of this extra-large bridge from the perspective of topography, hydrology, bridge type and cost. Finally, a (126+240+126)-m continuous rigid frame bridge is determined. The spans of this bridge are long and are appropriate for the complex terrain construction, which has a certain reference value for the selection of bridge structures in the mountainous areas.