The nondimensional differential equations governing the elastica of post-buckled coulmn with the variable cross-section are derived by third order theory, in which the shear deformation effect are included. These equations are solved numerically using a numerical integration technique and a bracketing method to obtain the first critical loads and the elastica of post-buckled columns. Three kinds of cross-sectional shape with simply supported end constraint are applied in numerical examples. The parametric studies of shear deformation effects on critical loads are analyzed and typical elastica of post-buckled columns with shear deformation and without are presented in figures.