Abstract: To meet the needs of the large scale scientific computations, a strongly decoupled parallel 3D mesh generation algorithm based on the AFT-Delaunay method is presented. For a given surface mesh bounding an arbitrary 3D region for meshing, a constrained Delaunay Triangulation method is employed to generate the initial tetrahedral mesh with few elements by a single thread. And then, an extended AFT-Delaunay method which can advance the front along a specific path is proposed to decompose the initial tetrahedral mesh region into sub-domains recursively and independently by introduction of a bisection plane. At last, each sub-domain is refined with the AFT-Delaunay method by a single thread in a decoupled manner. Experiments on several complex 3D models have been conducted, and hundreds millions of unstructured tetrahedral elements are generated automatically on the PC platform. This algorithm can guarantee the mesh quality of both the boundary of whole region and the interface between sub-domains, meanwhile, effectiveness and robustness are achieved.