Laser powder bed fusion (LPBF) offers manufacturing freedom for innovative designs of precision metal parts via layer-by-layer processing. However, the accompanying spatter during manufacturing contaminates the powder bed, introduces metallurgical defects, and compromises overall stability. To address these issues, this study numerically simulates the coupled dynamic behavior of LPBF molten-pool spatter based on the computational fluid dynamics-discrete element method (CFD-DEM) framework implemented the CFDEM open-source platform. The CFD calculation distinguishes between the liquid–metal, solid–metal, and gas phases using the volume of fluid and multiphase models, while the DEM calculation addresses metal particles, accounting for the influence of metal-vapor recoil force on particle motion. Employing a semianalytical CFD-DEM approach, this coupling framework circumvents the limitation imposed by the CFD mesh size. The simulation reproduced three typical behaviors of metal particles (thermal spatter, melting into the molten pool under laser heating, and falling into the molten pool without laser heating) and predicted the spatter-ejection directions under different process parameters. The numerical results were verified through comparisons with the experimental results. Finally, the influence of process parameters on the coupled dynamic behavior of molten-pool spatter was investigated, revealing that powder bed thickness dominantly affects the number of hot spatters, followed by scanning speed and laser power. The open-source code of this paper is available at https://github.com/caoliu0706/7-CFD-DEM-LPBF-Molten-Pool-Splatter.