At the most of executive project in Iran, using Tetrabromomethane (CBR+4) ion stabilizer solution is a chemical ion-exchange experiments. The necessity of present study is the investigation about the characteristics of strength behavior of clayey soils with various plasticity index (PI) stabilized by this method. The performance of stabilized soil samples by CBR+4 ion-exchange solution in wetting-drying and freeze-thaw cycles also been studied for the first time in this study. Firstly, in soil stabilization with CBR+4 solution the required amount of the stabilizer is determined, according to the amount of soils ion exchange, which is determined by a laboratory chemical test. Then, the samples are built in their optimum moisture content and maximum dry densities and after curing the samples for two weeks, dry samples are tested. Soils samples are also tested in saturated condition after two weeks curing time. Saturated samples showed more increase in strength compared to dry samples. Stabilized soil sample are also tested under 1 to 4 freeze-thaw and wetting-drying cycles. Tests results showed that using CBR+4 stabilizer increase bearing capacity of clayey soils. This increase is higher in soils with lower PI. Although freeze-thaw and wetting-drying cycles reduce soils bearing capacity, their strength are significantly more than the un-stabilized samples and is acceptable.