Abstract: Connectivity rate of plastic zone is one of the most important criteria of the finite element method for evaluating stability of soil slope whether or not it reaches instability.The criterion,however,is not uniformly recognized at present.Therefore,a quantitative study emphatically on the criterion for evaluating stability of homogeneous soil slope is discussed in this paper.At first,Considering the three main parameters(cohesion force c、angle of internal friction 、slope ratio )of the slope stability,parameters of the slope which is in limiting state of equilibrium are selected by traditional slice method.Secondly,the connectivity rate of equivalent plastic strain median in shear band of the slope is got by adopting the above parameters.At last,the criteria formula(y=0.020702c+0.024417-0.67898+0.46799)for evaluating stability of slope is put forward though the multiple linear regression.The example indicates that the safety factor calculated by the formula is in accord with the Bishop slice method.So it validates that the quantitative criterion for evaluating stability of slope is reasonable.