Abstract: Recently, the water discharge of the sixth steel pipe' s outside drain pipe of Tianhuangping pumped storage power station is on a high level , and the discharge is increasing .Further more , small detritus, sand, cement concretion and a little earth are carried out by the drainage. This phenomenon is abnormal. According to this problem, the author analyzed the causation along with the possible consequence and advanced disposal suggestion based on the design intent, the observation and test achievements.