The strain tests are carried out by FBG sensing technology for the structure of cylinder caisson on a 300 000 DWT oil harbor. Based on the LabView virtual instrument software development platform, the timeliness health monitoring system is established, to realize the timely monitoring of the stress of the main projects, timely identification of the cumulative damage of the structure, and assessment of the performance, and provide the early warning to the potential hazards and establish appropriate safety warning system, so as to improve the safety and reliability of the harbor. Through the monitoring results of the steel strain, we can learn more about the dynamic response of cylinder caisson structures under complex external environment, and it is of practical significance on research of similar structures.