In Vietnam, peat soils are formed by lake-bog or alluvial-bog sediments, which are widely distributed in the Mekong Delta such as Dong Thap Muoi area, Kien Giang, Hau Giang provinces, and U Minh forest. In soil often contains a lot of organic matter, low pH, strong alkaline soil. This will affect the quality of reinforcing soft soil with cement. The results of this study on improving them with local cement showed that the reinforced soil samples had initially increased until 28 days of age and then decreased with curing time. Additives play an important role in soil improvement with cement. They can change the hydrological environment making the soil reinforced better. In this study, we used lime (CaO) and gypsum (CaSO4.2H2O) in combination with local cement to improve the peat soil mentioned above. The results show that, when adding a small amount of lime, 1, 2, 4, 6% or 1, 2, 3 % of gypsum compared to cement, the reduction in strength with curing time has been reversed. The optimal content of additives has been determined as lime 4% and gypsum 2%.