Along with the continuous development of the economy and society，the national requirements for environmental protection are becoming increasingly strict. The excavation replacement and filling scheme is traditionally used to deal with deep soft soil foundation in port engineering，which has a great influence on the surrounding environment. Compared with the traditional scheme，the composite foundation of rotary jet grouting pile has less disturbance to undisturbed soil，weaker influence on surrounding water quality，less sea area occupied during construction，and less influence on the navigation of surrounding ships. However，at present，the composite foundation of rotary jet grouting pile is seldom used in the new vertical hydraulic structure，especially in the breakwater structure，and the block full jet foundation is mostly used. This paper introduces the application of the composite foundation of rotary jet grouting pile in the vertical breakwater of the Dalian Zhangzi Island，analyzes the structural characteristics and bearing capacity of the composite foundation of rotary jet grouting pile，so as to provide reference for the application of the composite foundation of rotary jet grouted pile in port engineering.