Additive　manufacturing　technology,　with　its　characteristics　of　no　mold　and　short　production　cycle,　provides　a　new　scheme　for　the　machining　and　manufacturing　of　high　performance　and　difficult　material　parts.　However,　the　forming　process　of　additive　manufacturing　is　non-equilibrium　solidification,　which　is　easy　to　form　uneven　microstructure　and　reduce　the　mechanical　properties　of　the　parts.　Special　energy　field　assisted　forming　technology　has　great　potential　in　improving　the　manufacturing　problems　of　high-strength　difficult-to-process　materials.　In　recent　years,　it　has　been　continuously　applied　to　additive　manufacturing　to　improve　the　microstructure　and　properties　of　parts.　Ultrasonic　assistant　is　an　important　method　to　reduce　the　residual　stress　in　the　additive　manufacturing　process,　and　its　scientific　principle　is　still　a　frontier　scientific　issue.　Therefore,　this　paper　uses　molecular　dynamics　(MD)　method　to　study　the　influence　of　ultrasonic　assistance　on　residual　stress　in　additive　manufacturing　process.　In　this　paper,　the　process　of　ultrasound-assisted　3D　printing　of　graphene　reinforced　aluminum　(Al)　matrix　composites　was　simulated　by　MD　method.　The　effects　of　ultrasonic　aid　on　grain　size,　orientation　and　dislocation　in　the　composites　were　analyzed,　and　the　mechanism　of　ultrasonic　aid　reduction　of　residual　stress　was　revealed,　which　provided　theoretical　guidance　for　ultrasonic　aid　additive　manufacturing　process.　©　2024　SPIE.