Abstract: This paper is based on the slope limit equilibrium theory and the circular sliding failure model of prestressed anchor and grillage supporting structures. It considers the effects of grillage and anchor on the stability of soil slope, and uses the idea of circular slice method. The calculation model for internal global safety factor and the search model for the most dangerous sliding surface are established respectively by applying integration method. The centre coordinates of sliding surface are regarded as geometrical controlling parameters. The function relation for variables in the calculation expression of safety factor and the centre coordinates of sliding surface is derived. Then the function relations among the geometrical controlling parameters of sliding surface and the internal stability safety factor are deduced. The centre coordinates of the most dangerous sliding surface of grillage supporting structure with prestressed anchor have been dynamically searched and solved using mesh method. Finally, the calculation program for stability analysis of the grillage supporting structure with prestressed anchor is compiled with the language Matlab. An engineering example is used to check the stability of the calculation program. The applicable conditions of the proposed method are discussed. The results show that this method is concise and applicable, which is more reasonable than the conventional empirical analysis methods.