Based on a steel truss footbridge under construction, numerical simulations of aerodynamic coefficients and pedestrian level wind environment on bridge deck of the steel truss section were conducted firstly using computational fluid dynamics (CFD). Finally, the aerodynamic coefficients, vortex-induced vibrations, and flutter instability of the steel truss footbridge were investigated with wind tunnel tests. The research results show that the cultural wall inside the steel truss has great effects on the pedestrian level wind environment on the bottom bridge deck. Appropriate increase of the gaps between the cultural wall and the bottom and top chords of the truss can effectively improve the pedestrian level wind environment on the bottom bridge deck. The aerodynamic coefficients of the steel truss with asymmetry section under the wind blows from left side are obviously different from that of the bridge deck under the wind blows from the right side. There is obvious vortex-excited resonance of the steel truss footbridge with asymmetry section. The amplitudes of the vortex-excited resonance of the steel truss footbridge can be effectively reduced with tuned mass dampers (TMD).