It　is　of　great　importance　to　thoroughly　explore　the　evolving　temperature　fields　of　direct　laser　metal　deposition　(abbreviated　as　LMD)　in　vertical　thin　wall　manufacturing.　It　is　helpful　to　control　the　temperature　gradient,　and　even　to　adjust　to　forming　microstructures　and　accumulation　of　residual　stress.　In　this　paper,　a　comprehensive　three-dimensional　transient　model　is　developed　for　evolving　temperature　fields.　The　manufactured　material　is　DS　superalloy　Rene80.　The　laser-powder　interaction　during　the　powder　flowing　process　is　simulated　first,　and　its　possible　effect　on　the　temperature　field　of　the　melting　pool　is　analyzed.　Then　a　3D　numerical　simulation　for　the　evolving　temperature　field　is　carried　out　based　on　considering　transport　phenomena　during　LMD　such　as　the　change　in　phase,　powder　injection　and　liquid　flow.　The　applied　deposition　parameters　are　derived　from　experimental　investigation　with　optimized　vertical　wall　manufacturing.　The　simulated　results　explain　why　a　balance　between　heat　input　and　dissipation　could　form　inside　the　vertical　thin　wall.　These　reconstruct　the　instability　at　an　early　phase　of　the　building　process　without　any　temperature　control　unit　and　exhibit　the　influence　of　parameters　such　as　laser　power,　deposition　velocity　and　laser　beam　deposition　pattern.　The　simulation　results　of　temperature　evolution　are　consistent　with　experimental　investigation.