Wind characteristics at a bridge site in mountain valley are very complicated, which leads to a new problem for the design and construction of long span bridges. To accurately obtain the wind characteristics in mountain valley and their distribution, the terrain model wind tunnel test of a V-shaped canyon where a long span bridge is going to be built with uniform and atmospheric boundary layer inflow conditions was carried out, and the mean and fluctuating wind characteristics at the bridge site under different wind directions were studied. The distribution of wind characteristics at the location of bridge tower and main girder was analyzed. And the main beam 1/6 span and the midspan of the V-shaped canyon in the boundary layer turbulent wind field under the inflow wind characteristics were compared. The results indicate that the wind profile suitable for flat terrain in the relevant wind resistance specifications cannot be directly applied for mountain area, and the range of wind attack angle changes in the canyon is large. The suggested wind attack angle range for V-shaped valleys is -20° to +20°. When the flow direction and the valley orientation are consistent, the turbulence intensity is also smaller, while the turbulence intensity of the leeward side of the bridge is large, so the leeward side of the bridge should be reinforced during the design. The fluctuating wind power spectra at the middle span of main girder and the pylon are in agreement with the von Kármán spectrum. This study could be provided reference for wind resistance analysis and design of long span bridges in similar V-shaped canyon in mountain areas.