Abstract: Laser Powder Bed Fusion (LPBF) is a mature technology of metal additive manufacturing, with the advantages of high forming accuracy, parts density close to 100%, which is suitable for complex structure, small size and high precision parts. LPBF technology has been used in aerospace, automotive, mold and medical and other fields. LPBF forming process integrates complex multiple physical and chemical phenomena from nano and micrometer to macroscale. LPBF is the non-equilibrium freezing behavior of extreme speed cooling and micromelting pool. It is difficult to analyze and measure the temperature and melting pool size by experimental means during the forming process. The physical and chemical phenomena of heat transfer, mass transfer, and collision of LPBF process were introduced firstlly .In additionally, the development trend of macroscopic mechanics, powder bed dispersion element, wind field, melting pool, microscopic organization and structure optimization in LPBF forming process were reviewed in this article.