Drainage system is an important part of highway design,and it hasanessential effect of ensuring the running quality and life-span of highway.This text directs towards the drainage system of Le Wen Highway,primarily to introduce the design of median divider drainage,surface drainage,side drain of roadbed drainage and intercepting drain of cutting excavation drainage.Besids,there are some design practices and specific mechanical control measures according to the coordination between highway drainage system and surroundings,which can offer a reference for drainage design of slightly precipitous plains.