Abstract: Because of the complicated boundary geometric features of multi-solid models, the algorithm for grid-based hexahedral mesh generation had very weak stability and generated some poor boundary elements. According to these problems, an algorithm for the automated generation of grid based all-hexahedral element meshes is developed. In the surface matching process, a surface matching algorithm combining the embedding technique is proposed, establishing the corresponding the boundary element relation between solid models and core mesh, and making the hexahedral mesh accurately describe the geometric features of multi-solid models. In the topological optimization process, an optimization technique eliminating the hexahedral elements with bad topological connection is proposed. The effectiveness and robustness of the algorithm in this paper are tested by means of some solid model examples.