The dredging project of Yancheng Binhai port area has complex working conditions and uneven soil stratification，the upper silt has the characteristics of small particle size，dense and hard，the power of cutter fluctuates obviously during ship construction. The density of subclay soil in the lower layer is high，and the long row distance of 14 km is easy to cause pipe blocking. There are many blocks and obstacles in the construction area，and the suction and pump blockage often occur. For the newly-built ship “HAO HAI LONG”，the applicability of different cutter stone prevention schemes is analyzed by replacing the cutter to find the balance point between mud concentration，flow rate and construction efficiency，and the ship machine performance is tested. The results show that when excavating dense silt，the use of general cutter can increase the soil breaking capacity and reduce the fluctuation amplitude and frequency of cutter power. The installation of steel grating at the suction port can effectively reduce the blockage of suction and pump. When excavating the lower layer，the balance between productivity and transportation efficiency can be achieved by properly reducing the mud concentration.