Taiwan is located in the subtropical zone,and the temperaturerise problems which possibibly occur in the long tunnels of freeway should be emphasized.After the Completion of the Syueshan tunnel,in the beginning only the passenger cars are permitted to pass through this long tunnel,and now the highest temperature in the Syueshan tunnel is under 40℃, in the next stage facing the situations of opening buses passing through Syueshan tunnel,it is estimated that the temperature will rise to 50℃,and schemes of cooling should be adopted.After the acting of the Ventilation System in the tunnel,the coolingeffect will make the highest temperature remain under 40℃.