Subsidence deformation of dredger fill sea sand in Qidong City, Jiangsu Province, was studied using a consolidometer. Dredger fill sea sand with a subsidence coefficient of 1. 1%, which is less than the subsidence coefficient of the subgrade filling material of a highway, i. e. , 1. 5%, can be used as the subgrade filling material. Sea sand samples with different salt contents were prepared by adding different quantities of NaCl to investigate the effect of the salt content and pressure on the subsidence coefficient. It was found that the subsidence coefficient increased with the salt content and reached the maximum value when the pressure was 200 kPa.