Aiming at the problems such as high drilling depth,high safety requirements,large amount of engineering,tight schedule for Linchijiao Reef project of Meizhouwan Channel Phase III，this paper analyses field geological conditions,pore network parameters,differential time,explosive consumption of single-stage,seismic wave intensity etc.The millisecond blasting technique,which combines inside the hole with outside the hole,can effectively solve the problems in the construction，to ensure the safety of the surrounding wharf,tanker ships and submarine pipelines.The construction progress is accelerated,and the construction tasks are completed successfully.