In order to improve the efficiency of sand extraction in the open sea by large trailing suction hopper dredger in Xiamen Airport phase II project，we analyze soil characteristics of loading and overflow in different sand extraction areas and existing loading construction problems，and summarize main reasons for the reduction of construction efficiency in different sand extraction areas.Then we propose the optimization technology of sand extraction and loading construction in open sea according to different soil characteristics，which is verified and applied by the on-board test.The results show that there are differences in the sand extraction and loading technology of different soils.For the soil condition with easy deposition and small overflow loss，improving the flatness of cabin can effectively increase the loading soil volume.For the soil condition with difficult deposition and large overflow loss，promoting the ability of excavation is an important mean to improve the efficiency of sand extraction and loading.