To accurately determine the limit carrying capacity of reinforced concrete slabs, based on the classical yield-line theory and previously proposed stress failure criterion, this paper presents the modified segment equilibrium method which incorporated the effect of the tensile membrane action. Additionally, the nonlinear finite element procedure was established according to the flat shell element and elastic-plastic theory. The two methods were used to calculate the limit load carrying capacity of reinforced concrete two-way slabs, and comparison between the calculated results and experimental results were conducted. This study shows that the two methods were clearly capable of predicting the load carrying capacity of the concrete slabs with reasonable accuracy, because the tensile membrane action was taken into account in the two models. Compared with the finite element model, the present method has strong engineering application value, due to its simple principle.