To explore the influence of wind speed on the smoke temperature and distribution characteristics of the bifurcated diverging tunnel fire, Hangzhou West Station Tunnel on National Highway G235 was taken as the engineering background in this paper. The numerical simulation method was used to investigate the influences of different upstream wind speeds and fire source positions on the fire smoke propagation in the diverging expansion section. The results indicate that: ① A higher wind speed at the tunnel entrance results in a shorter smoke backflow length in the tunnel, and the rate of smoke backflow in the tunnel decreases accordingly; ② The temperature near the side wall close to the fire source in the expansion section is higher. As the fire source moves laterally towards the ramp, the vault temperature in the main tunnel decreases while that in the ramp increases. A higher tunnel wind speed leads to a lower maximum vault temperature in the tunnel;③ When the longitudinal ventilation in the tunnel encounters fire smoke, convection forms, causing the smoke flow velocity in the tunnel to decrease, while the smoke flow velocity at the fire source increases sharply.