Abstarct: In this thesis, in order to consider the effective parameters on the critical buckling load, in symmetric laminated composite plates with regular polygonal hole, using genetic algorithm (GA), to introduce the optimum parameters to achieve the most critical buckling load. Design variables include the geometry of cutout, bluntness, rotation angle of cutout, fiber angle in symmetric laminated plates. The finite element method has been used to verify the accuracy of analytical results. Comparison of two methods demonstrates the accuracy of present analytical solution. In this study, an analytical method was used to calculate buckling load. According to this method, the first-order shear theory solving method was generalized by using conformal mapping to other holes. The results presented in this paper show that by selecting appropriate shape of hole and optimal parameters related to perforated symmetric laminated plates, the critical buckling load can be significantly increased, and even achieved to more load buckling than the buckling load in circular cutout. In other words, contrary to the expectation, the circular hole is not always the best geometry for increasing buckling load, and in some cases, by choosing the appropriate bluntness, rotation angle of hole and the angle of the fiber for plates, there can be more buckling load than the circular hole.