Abstract: The c ement stabilized soil in natural condition, as well as stabilization in corrosive site, will be influenced by e nvironmental pollution such as acid rain, seawater invasion or industrial pollution, which will lead to deterioration of the structure. Especially in the corrosive site, the strength of soil stabilized by cement will increase, but at the same time, it will decrease due to the deterioration at the beginning of stabilization. Th e experimental work is performed to study the strength of soil stabilized by cement in the corrosive site which is represented by sea water. Laboratory tests a re carried out to measure the strength distribution by means of the micro cone penetration test s . Also, the element analysis test s using the ion chromatography to measure the distribution of Ca²⁺ within the specimen a re conducted. The effect of seawater pressure o n the strength of cement stabilized marine clay is analyzed . Two conditions a re prepared. In t he first condition, two meters of seawater pressure are applied to the specimen by using vertical pipe filled by seawater, and the other specimen has no pressure applied. It is indicated that the deterioration extend s quickly under seawater environment and the deteriorated depth bec om e s deeper with the increase of pressure . The element analysis show s that the concentration of calcium ion s in deteriorated portion is lower than that in non deteriorated portion.