The invention relates to a belt type hydraulic conveying device and belongs to the field of mine equipment. The belt type hydraulic conveying device comprises a water tank, wherein a conveyer belt capable of floating on the water surface is arranged in the water tank, and turnabout drums capable of changing the rotation direction of the conveyer belt are arranged at the two ends of the conveyer belt; a water inlet hopper is connected to the side face of one end of the water tank, a water inlet pipe is arranged above the water inlet hopper, an electromagnetic gate valve is arranged on the water inlet pipe, and the water inlet pipe is connected with an underground water supply pipeline; a drainage pipe is connected to the bottom of the other end of the water tank and connected with an underground drainage system. A conveyer is driven by means of the potential energy of mine water, so that utilization of clean energy is realized; the conveyer belt can float on the water surface and is provided with low-density filler; an upper conveyer body floats on the water surface, power consumption caused by friction is reduced greatly compared with conventional conveyers, and therefore energy is saved; the initial investment on the conveyer is reduced, and a driving part of the conveyer and a complicated electrical control system are omitted.