Based on the flow theory and Orbisons yield surface, an efficient model of gradual plastic-hinge for space-framed structure analysis is presented in the light of lumped plastic assumption and the corresponding elastio-plastic stiffness matrix is derived. The model can accurately depict the effects of inner gradual plastic-hinge and the internal forces redistribution. The elastic and inelastic analysis can be implemented by using the same model with the condensa- tion technique to eliminate the internal freedoms. Theoretically, the model is accurate and shows its advantage in structural advanced analysis. Its validity is verified by several numerical examples.