Abstract: The present application relates to a suction dredger for use on an underwater hard soil layer and relates to the technical field of bridge construction equipment. The present suction dredger includes a mud suctioning mechanism, a mud-breaking mechanism, and a blockage-prevention assembly. The mud suctioning mechanism includes a pressurizing assembly and a suction dredging pipe. The suction dredging pipe passes through the pressurizing assembly and the two ends thereof at least partially extend past the pressurizing assembly. The side wall of the section of the suction dredging pipe located in the pressurizing assembly is provided with multiple pressurization holes that are inclined upward in the direction from the outer wall to the inner wall. The pressurizing assembly is used for, via the pressurization holes, forming low pressure in the suction dredging pipe. The mud-breaking mechanism includes at least two mud-breaking assemblies.