This paper deals with two-dimensional plane stress wrinkling model of elastic/plastic annular plate. Based on energy method and nonlinearity of strain-displacement law, a bifurcation functional in polar coordinate is derived analytically. This technique leads to the critical conditions for the onset of the elastic/plastic wrinkling of the flange during the deep-drawing process. Tresca yield criterion along with deformation theory of plasticity are utilized and the material of the plate is assumed to behave perfectly plastic. Moreover, the influence of the blankholder upon wrinkling and on the number of the generated waves is quantitatively predicted by the suggested scheme. The main advantage of the proposed solution is its better agreement with the experimental and analytical results found by the other resarchers.