Expansive soils change their volume due to changes in moisture condition. The volume change characteristics of this soil lead to different problems for structures constructed on it. To minimize the impact of the expansive soil should be treated or replaced by a suitable material to improve its mechanical property before any construction work is undertaken. In this study, cement, blast furnace slag and combination of cement and blast furnace slag in different percentage with 7 and 28 days of curing period were considered. The improvement effect of the stabilizers was then determined by using both the classical soil mechanics approach and the degree of saturation. The degree of saturation (S-SWCC) data points were established by combining the Shrinkage curve (SC) and gravimetric water content w-SWCC data and the corresponding fitting parameters of Fredlund and Xing (1994) were determined. The experimental results indicate that SWCC is affected by stabilizers and there is a change in the SWCC parameters, parameters ‘‘a’’, “n’’ and “m’’ were increased with an increase in the percentage of stabilizers and curing period. The volume change is 76.38% and 9.25% for untreated and treated soil sample, respectively, from the SWCC and SC,ans it is found to be a very good indicator of the effectiveness of treatment methods. In addition, using empirical equations, at 13% cement content falls into the medium degree of expansion, but considering suction at 11% cement content with a 7-day curing period, it falls into the low degree of expansion. This indicates that there is a potential for the SWCC to be used as a tool for evaluating the improvement effect of treatment methods. Keywords: Expansive soils, Blast Furnace Slag, Cement, Soil-water characteristic curve (SWCC), Unsaturated soils, Soil stabilization, Shrinkage curve.