Moment slope displacement equations of beams with two end semirigid connection restraints are covered. The evaluation of column effective length factor both braced frames and unbraced frames with flexible joints is derived. Determination of column effective length method proposed herein is. exactly the same as those of rigid frames which was well established in Chineses Specification of Steel Structures, however, the restraining stiffness of girders to columns should be amended semirigid connection is applied.