Abstract: In order to investigate the impact of different slope composition on the fire environment in the tunnel with herringbone slope, the effects of different tunnel slope combinations and fire heat release rate on smoke spread and temperature distribution under natural ventilation were analyzed by the numerical method.The results show that when the slope of the small-slope side tunnel is 1%, the natural induced airflow speed and fire environment are significantly affected by the slope composition on both sides of the variable slope point, and the induced airflow speed is proportional to (Q^*H'^*)0.113 6.When the slope of the small slope side tunnel is not less than 3%, the impact of the slope composition on both sides of the variable slope point could be negligible.Empirical equation for the maximum temperature rise in the herringbone tunnel was drawn, the maximum temperature rise in this kind of tunnel is much higher than that in the horizontal tunnel, and the safety of the tunnel ceiling above and close to the fire source should be concerned.