Abstract: An optimal topology model is established based on ICM(independent continuous mapping) method- ology in order to study the topological optimization of continuum structure with stress and displacement constraints under multiple load cases.The optimal model includes two types of dimensionless constraints which regard the structural mass as an objective.The transformation of the local stress constraints into the global stain energy constraints is achieved by adopting the strategy of globalization of stress constraints.As a result,the numbers of constraints is reduced,and the complexity of the sensitivity analysis is avoided.And an explicit formulation of displacement which relates to topological variables is presented by using of unit virtual load method.In addition,the dual model corresponding to the optimal model of continuum structure is established by the serial quadratic programming.Consequently,the number of design variables is decreased, and the efficiency of computation is improved.Numerical examples of the two dimensional thin plate structures indicate that the method is effective and efficient.