青藏铁路昆仑山隧道位于青藏高原昆仑山北麓乱石沟西测，海拔高度4000m以上，属多年冻土地区，隧道全长1686m，目前为世界最长的多年冻土隧道，于2003年9月建成。隧道贯穿多年冻土层，为减少隧道贯通后衬砌内外侧的热交换，使围岩中的水处于冻结状态，避免大量漏水，采取以堵为主，防、截、排、隔热、保温等多项措施。故多年冻土隧道的防、排水处理，具有一定的特殊性，也是重要的技术问题之一。结合工程实践，介绍多年冻土隧道防、排水有关设计和施工工艺。

Kunlunshan tunnel on QinghaiTibet railwayis located on the west of Luanshigou at the north foot of Kunlunshan Mountain, which, with over 4000m absolute elevation, belongsto permafrost region. Kunlunshan tunnel, with a total length of 1686m, is so far the longest permafrost tunnel in the world. The tunnel was completed in September, 2003. Since Kunlunshan tunnel penetrates through permafrost ground, a series of countermeasures are taken, which include the key measure of water blockingand otherassociated measures such aswaterproofing, water cuttingoff, drainage, thermal insulation and temperature keeping, so as to minimize the heat exchanges between the inner side and outerside of thetunnel lining and to keep the water contained in the rock mass in frozen state after tunnel breakthrough. Therefore, the design and constructionofwaterproofingand drainage of permafrosttunnels have their own particularityand areimportant technological problems to be solved. On basis of engineering practices, in the paperthe author presents the design and construction of the waterproofing and drainage of Kunlunshan tunnel.