To meet the strict environmental requirements of a reclamation project in Hongkong，we transformed the common cutter suction dredger and put forward a construction technology of filling sandy soil by cutter suction dredger with sand bucket device. Given the problems such as low construction efficiency，sand filling leakage and sand bucket plugging，and based on cutter suction dredger with sand bucket device with nominal capacity 2，000~3，000 m3/h，we have adopted the methods of experiment analogy and field data collection and demonstration，and have put forward key points of efficiency control，environmental protection measures and the idea of grid reconstruction. We have figured out the optimal working conditions of the dredger under different sand conditions. The results show that the average efficiency of mechanical sand can reach more than 800 m3/h，and the average efficiency of sea sand can reach more than 1，500 m3/h. At the same time，the cost is reduced and the environment is protected.