Abstract: This paper researches three techniques of drainage system with underground pipe lines of Xixiayuan reregulating reservoir stilling pool. The floodgate anti-seepage stability is analyzed and the horizontal and vertical anti-seepage and watertight layout form are fixed. The volumes of pump-out and displacement are calculated and the pipe diameter and equipment of pump-out and displacement are selected. The geological conditions is analyzed and the drainage pipes and sump are set reasonably.