Abstract:This paper briefly introduces the main methods which were applied to treat the defects of leak of tunnel lining on Nan-Kun railway(west-section),including the grouting on the back of lining, grouting inside of the lining,the spray of mortar waterproof layer,leaking stoppage by filling cracks, drainage by setting canals,etc. As well,the cause of formation of the defects are analyzed,and the thinking of treatment to them are presented. They are valuable as reference for the design and construction of waterproof and drainage.