The utility model provides the technical scheme of a draining device for a wet electric dust collector. According to the scheme, the draining device comprises a blow-off pipe communicated with the lower end of an electric dust collector ash bucket; at least two water outlet pipes are arranged on one side of the blow-off pipe; the blow-off pipe is communicated with each water outlet pipe through an overflow pipe; water outlets of the overflow pipes are located at different heights of the blow-off pipe; the height of a water inlet of each overflow pipe is lower than that of an overflow opening; the height of the overflow opening of the overflow pipe at the uppermost end is lower than that of a cathode framework of the electric dust collector; the blow-off pipe located at the lower part of the water inlet of the overflow pipe at the bottommost end is provided with a blow-off valve; and each overflow pipe is provided with an overflow valve. According to the scheme, the blow-off pipe is communicated with at least two upwards-inclined overflow pipes from bottom to top; and if the overflow pipe at the lower part is blocked, the overflow pipe above the blocked overflow pipe can still have an overflow effect, so that the safety operation of the electric dust collector is ensured.