The invention belongs to the technical field of dredging equipment, and particularly relates to a small dredging device with energy supplied by water and electricity. According to the small dredging device, current with natural potential energy or current of water supplied by a water pump is used for impacting a vertical impeller to drive a transmission shaft to upwards stir sludge and convey thesludge to a sludge conveyor belt, the current impacts a front horizontal impeller and a rear horizontal impeller, the horizontal impellers rotate to drive the sludge conveyor belt to move through a belt so that the sludge can be transported to the sludge conveyor belt and discharged out of a discharge hopper. A sludge absorbing hopper of the device directly stretches into the sludge, in the dredging process, an upper clear water layer is not prone to being puddled, little or no effect is caused to the upper clear water layer, and dredging without stopping water can be achieved; pretreatment can be carried out on the removed sludge, the moisture content of the sludge is reduced, and later transportation is facilitated; and independent energy supplying or collaborative energy supplying of the electric energy and the water energy can be achieved, energy sources are saved, the massive structure is simple, the size is small, the small dredging device is suitable for a small dredging place,and the dredging effect is better for a round funneling pool bottom.