Abstract: Niutoushan Reservoir has been paid more attention to its seepage since1993, so it was checked by reservoir emptying.Based on analysis of water resource and seepage passway and other factors concerned as well, the author considered that seepage have not resulted from facing’s anti-seepage preperties decreasing, and at present it can not bring dam into danger. In addition, by-pass seepage around left dam shoulder has been discussed and the dam seepage is considered to be safe in general.?