A series of tests were carried out to study the deterioration of soil cement in the Yellow River delta, and the suppression effect of different additives(fly ash, GGBS(ground granulated blast furnace slag)) on the soil cement deterioration. X ray diffraction analyzer and scanning electron microscopy(SEM) were employed to study the deterioration mechanism of the soil cement and the modification mechanism of additives material. Results indicate that the underground salt water is significantly corrosive to soil cement. Compared with the normal soil cement, the compressive strength of salty soil cement was 18.5% lower after 90days and 21.6% lower after 180days. With the addition of fly ash, the initial strength of salty soil cement decreases, however, the long term strength increases gradually. GGBS can significantly increase the strength and enhance the ability of restraining deterioration of salty soil cement. It is suggested that replacement of 60% Portland cement by fly ash and GGBS, with the amount of GGBS not less than 40%, can form an employable material, which is able to effectively prevent the deterioration of salty soil cement.