Abstract: Considering the characteristics of swelling soil,a new reinforcement approach,called self-balance pre-stressed bolts reinforcing technique,was developed.In this method,the merits of grout bolts were combined with those of pre-stressed ones,and the reinforced structures were constructed by pre-stressed equipment,which included anchorage section and free section,but the initial pretension was small or null.When the soil swelled with the increase of its saturation,the bolts would be stressed enough to make the slope stable,so the slope and bolts would form a self-balance system.Based on the compatibility condition of the deformation between bolts and soil,the equation of the initial pretension was derived.At the same time,how to analyze by use of finite element method was described.It was shown by theoretical and numerical analysis that the self-balance pre-stressed reinforcement approach could increase the stability and decrease the deformation of expansive soil slope effectively,and its cost was reasonable.So the reinforced technique was recommended.