This　article　presents　a　centroid　variability　model-based　controller　of　HITUWV　(Underwater　Welding　Vehicle　by　Harbin　Institute　of　Technology),　an　underwater　welding　vehicle,　for　automatic　welding　with　high　stability　and　accuracy.　First,　an　accurate　centroid　variability　model,　which　considers　the　coefficient　changes　of　the　HITUWV　caused　by　the　movements　of　a　3-degree-of-freedom　manipulator,　is　presented　to　perform　the　dynamic　characteristics　of　the　HITUWV　precisely.　Second,　a　centroid　variability　model-based　adaptive　sliding　model　controller　is　developed　for　the　HITUWV　to　complete　centroid　variability　compensation.　Experimental　results　indicate　that　the　proposed　centroid　variability　model-based　adaptive　sliding　model　controller　demonstrates　better　performances　in　stability　and　accuracy　than　the　conventional　proportional-integral-derivative　controller　and　the　model-based　proportional-integral-derivative　controller.　As　a　result,　the　centroid　variability　model-based　adaptive　sliding　model　controller　holds　great　practicality　and　utility　on　the　control　of　underwater　operation　with　high　stability　and　accuracy.