Abstract: It is very significant to study the key technology in taking the dredged soil as new construction material in the port engineering considering the resources shortage and environmental restriction. The traditional point-supporting measurement technology could not be utilized to measure the deformation of a large filling bag in its filling and loading process. The engineering practical problems such as measuring the deformation of large filling bag with dredged high clay content soil have received much concern at the present stage. Based on the laboratory calibration tests and filed prototype tests， the selection of the optic fiber sensor， cemented fixation and protection， measurement accuracy and error analysis， and application testing studies in the filed works have been carried out. The application feasibility of the distributed optic fiber sensor to measure the deformation of the large filling bag with dredged soil is discussed. The research results show that the optic fiber sensor with flexible sheath should be adopted for measuring the deformation of the large filling bag with dredged soil. And the measurement accuracy would be up to ±30 με with the apposite optic fiber sensor, the monitoring spatial resolution could be 0.1 m, and the maximum strain measurement range could be within 30 000 με. The distributed optic fiber sensor could be adopted as a new reliable method to monitor the deformation of the large filling bag with dredged soil.