The load-transfer modelling of soil mixing anchor is regarded as taking the coupling of dual-interface slip into account. It is essentially caused by the mobilization of bond strength for both the reinforcement-binder and the binder-matrix interfaces, and the impact of stress and strain conditions of materials adjacent to the interfaces on the propagation of interface shear stress. A recently developed load-transfer modelling framework of soil mixing anchor accounting for coupling of dual-interface slips was presented in this work based on interface characterization. This framework was established by integrating load-transfer method and shear displacement method, conventionally used in anchor behavior analysis, to solve for the straining of soil mixing anchor induced by interface shear stress in axial and radial directions, respectively. Laboratory testing including mechanical characterization of cemented soils, pullout tests on soil mixing anchor using elementary specimen and model specimen were carried out to calibrate the parameters in modeling and to validate the predictive capability for the pullout response of the presented modelling framework.