Abstract: Under the condition that all the perfectly plastic stress components at a crack tip are the functions of θ only, making use of equilibrium equations and Von-Mises yield condition containing Poisson ratio, in this paper, we derive the generally analytical expressions of perfectly plastic stress field at a stationary plane-strain crack tip. Applying these generally analytical expressions to the concrete cracks, the analytical expressions of perfectly plastic stress fields at the stationary tips of Mode Ⅰ, Mode Ⅱ and Mixed-Mode Ⅰ-Ⅱ plane-strain cracks are obtained. These analytical expressions contain Poisson ratio.