Abstract: The boundary layer is a thin layer close to the object surface in fluid motion, and high-quality boundary layer grids are the basis for obtaining accurate results in aircraft fluid dynamics calculations. In response to this issue, this paper proposes a high-quality unstructured construction method for boundary layer mesh generation. This method can effectively avoid the local self-intersection problem during the advancement of traditional unstructured boundary layer mesh generation methods, thereby ensuring the quality of the global unstructured boundary layer mesh. This unstructured construction method can not only generate high-quality unstructured boundary layer meshes, but also significantly improve the quality of the background tetrahedral mesh to be generated, and has the characteristics of high flexibility and strong plasticity.