Stability of steel structure is an important factor to determine its bearing capacity, which can not be ignored in the design of steel structure. Improper design or structural measures of beam-columns may lead to overall or local instability of steel structure, resulting in structural damage, so it is of great importance to analyze and discuss the stability problems of steel structure in engineering practice. This paper studied the flexural prop- erties of the beam column of steel structure uniaxial symmetry under the influence of lateral load and concen- trated load and analyzed the internal force of steel beams in almost two kinds of loads and deformation so as to provide some reference for the stability design of steel structures.