This paper analysis the theoretical formula of elastic buckling load of the frame structure .The analysis involves lateral and non lateral frame ,and the frame involves different forms of bearing constraints .Come up with the theory that elastic buckling load of the frame structure(P_cr) have a relationship with stiffness ratio of Beam and column (K_1).Draw a curve of P_cr-K_1,and find out the range of K_1 which P_cr Increased rapidly. Finally conclude that P_cr and K_1 have a Positive correlation when K_1 at the low level , with the increase of K_1,the Growth rate of P_cr slows down . At the same level of K_1,the P_cr of non lateral frame structure outweigh the lateral frame structure.