It is important to determinate the shear center of beam having arbitrary cross-section in structures. In this study, we have introduced the determination of shear center that gets the equivalent stiffness matrix representing arbitrary cross section of beam and applies energy equivalence theory. This method shows the results of applying on examples that we know the exact and approximate solution of open and cross section of beam. This study also compares with the shear center of composite rotor blade got by the experiment and by the suggested method.