Abstract: The topology optimization of large and complex structures is important in theory and application. Based on the idea that finite elements with artificial material property are inserted around the cavities and boundaries of the structure to approximately transform the singular topology optimization model into a non-singular one, this paper has made a research on the topology optimization problem of large three-dimensional continuum structures considering displacement requirements. First, a criterion and a set of formulas of three-dimensional structures with displacement constraints are introduced. Then, in order to solve calculation efficiency problem of large structures with more than ten thousand degrees of freedom, a strategy and its algorithm of three-dimensional structural topology optimization designs are proposed based on analyzing the computation model of structural properties and combining with the iteration method of structural displacement calculations. Finally, several examples of typical and complex three-dimensional structural topology designs are given. These examples show that the proposed method is valid and effective for complex three-dimensional structural topology optimizations, and is of engineering application value.