There are many accidents in the construction of a structure owing to the collapse of concrete formwork. It is usually occurred in many cases because of the buckling of slender column members in system support. So, recently, it is considered more important that the buckling analysis results must be checked in the design of system support. Therefore, in this study, methods for the computer program development based on linearized buckling analysis algorithm using subspace iteration method are investigated first, then some algorithms available in case of a computer program development are studied on the basis of investigated methods. On the basis of studied algorithms, a computer program sNs is developed and the results by this program is compared with the results by theory and structural analysis programs - SAP2000, MIDAS - for the verification of their accuracy.