To address the low efficiency of cutter suction dredgers in dense sand and silt of coastal ports in China，we carry out an experimental study on the excavation of dense silt and obtain the excavation resistance characteristics of the dense silt. According to the cutting characteristics of high-power cutters for dense sand，we optimize the section shape of cutter arms and establish a three-dimensional（3D）model of cutters to analyze their stress when cutting sand and their stress and deformation at the maximum power. On this basis，we develop a dense sand cutter. The application of the research results in a cutter suction dredger shows that the productivity of the dense sand cutter is significantly higher than that of the original ones under the same working condition.