The utility model discloses a water -storage uses power failure alarm device in power station, including the casing, the inner wall of casing is equipped with the fixed plate, the upper end of fixed plate is equipped with the static contact, the bilateral symmetry of static contact is equipped with the fixed block, two the one end that the fixed block was kept away from to the telescopic link is equipped with the mounting panel, it is equipped with the sealing washer to encircle between mounting panel and the shells inner wall, the bottom of mounting panel is equipped with the movable contact spring, the bottom of static contact and movable contact spring is connected with first wire barrel respectively, static contact and movable contact spring all are connected with the power through first wire barrel, which comprises a housin, the bottom opposite side of siren is connected with the second wire barrel, the one end that the siren was kept away from to the second wire barrel is equipped with the block terminal. The utility model discloses simple structure, the warning effect can be played in easy operation under the multiple condition, the loss of reduction unnecessary, it is convenient ingenious that the device uses, suitable extensively popularization.