Rainfall has a greater negative impact on the traffic safety and efficiency in the mountain breeze transit road of mountain highways.In order to ensure the traffic safety on the mountain breeze transit road in rainy days,improve the traffic efficiency,and reduce the adverse effects of the wind-rain coupling,an overall scheme of the variable speed limit system in rainy days is designed for the mountain breeze transit road,and a calculation model of the safe speed under the coupling effects of wind-rain is constructed based on the anti-sideslip and the safe stop- ping sight distance.Then,an evaluation model of the variable speed limit system,which aims to minimize the ave- rage travel time of the vehicle in the monitoring period,is also constructed.Finally,the simulation experiments based on the actual road and meteorological data are carried out by using the Matlab software.The results show that,as compared with the fixed speed limit,the variable speed limit has a better performance in guaranteeing the traffic safety on the mountain breeze transit road of mountain highways in rainy days，and it improves the operating efficiency of vehicles accordingly.