Abstract: In order to study the inelastic dynamic response of three-dimensional reinforced conceive frames, the multi-dimensional restoring force model is extended from one-dimesional degrading type of trilinear hysteresis rule by using the associated plastic flow rule and Mroz's hardening rule. An algorithm is designed for space reinforced concrete frames, The rationality of this model and the program are verified with the test results of the reinforced concrete frame which has plane eccentricities by non-coincidence of centers of mass and stiffness.