Abstract: There is no effective method to analyze and calculate the stability of supporting structure with prestressed anchors, especially when the influences by prestress are taken into account. Valid quantitative analysis methods are rarely given in documents published. From plenty of literatures on qualitative analysis, the prestress exerted on the anchor plays a positive role in improving the stability of slope. The soil stress state is transformed by the additional stress caused by the prestress, thus the stability of slope can be enhanced. The prestress is treated as a concentrate force and discomposed into horizontal force and vertical force, so as to estimate the additional stress in the soil and analyze the stability of slope. By this method, the reinforcement of the prestress is embodied, and the stability analysis of supporting structure with prestressed anchors will be more precise and reliable. Moreover, analytical calculation shows that the method can be simplified to consider the horizontal force and ignore the vertical force when the anchor inclinations are among the common range.