Abstract: A sample of a particular soil from Zhan-jiang coastal area is studied. The engineering properties of the soil seem to be poorer from the physical index, its natural water content is 40~45%,void ratio 1.17~1.28 and liquid limit about 66%.But,according to the mechanical index,its engineering properties seem to be better,unconfined pressure strength is about 5~6 kg/cm2, and apparent preconsolidation pressure about 9 kg/cm2. Besides,the properties of this soil before and after it is dried in air have obviously changed,liquid limit decreases by 14~18% and friction angle φ increases by 3~6°Polarization microscope,scan electronmicroscope and X ray diffractometer are applied separately to view and determine the fabric characteristics and orientated range of flat particles in samples. The bond action of the cement material between fabric and particle units is researched also. A construction model is presented to relate genetical source of some particular nature of Zhan-jiang soil.