Great progress has been made in topology optimization in the past decades, but most research work focused only on the topology design of single-component structures.As most real life engineering designs are actually based on multi-component systems, the design of multi-component structures is of greater relevance.In this paper, a study on integrated layout optimization of discrete components and continuous supporting structures is presented.An efficient algorithm based on the stiffness spreading method (SSM) for determining the locations and size of discrete components in a simultaneously optimized supporting structure is developed and some numerical examples presented to show the efficiency of the proposed model.Firstly, the stiffness spreading method (SSM), which was proposed by the authors previously for layout optimization design of truss structures, is introduced.And the authors extend it to formulate a novel model for the integrated optimization of the layout of discrete components and continuous supporting structures.In the proposed model, movable discrete components are introduced into the design domain.The stiffness matrices of these discrete components are replaced by a set of relaxed equivalent stiffness matrices and embedded into the background structure based on the SSM, and their locations and sizes can be optimized with the supporting structural topology simultaneously.Then the proposed optimization model is discussed.The locations and the size of the discrete components and the pseudo-densities of the supporting structure are assigned as the geometrical and topological design variables respectively.All sensitivities required for the optimization can be easily obtained and calculated by analytical methods, thus highly efficient mathematical programs can be easily implemented into this model.The Method of Moving Asymptotes (MMA) is used as the optimizer in this paper.The model of Solid Isotropic Microstructure with Penalization (SIMP) is used for the continuous supporting structures optimization and no remeshing is required during the optimization process.Based on the proposed model, several mean compliance minimization problems are studied subject to material volume constrain.Two types of discrete components, separate bars and substructures consisting of bars, are considered.Numerical examples illustrate the feasibility and efficiency of the proposed method.Finally, some conclusions are made.