As a key equipment in polyvinyl alcohol recovery section,acetic acid concentration tower plays an important role of re-cycling acetic acid in production system.However,due to the harsh acetic acid corrosion environment inside the tower,even if the anti-corrosion level of present material is upgraded to titanium,corrosion problem still remains prominent,thus leads to a shortened operating cycle of the plant and a decrease in economic benefits.On the basis of on-site corrosion investigation,cau-ses,processes and corrosion protections of TA2 tray failure were studied by applying methods such as material element analysis,scanning electron microscopy(SEM)and X-ray diffraction(XRD).The findings indicated that TA2 corrosion and hydrogen em-brittlement are main causes.Corrosion environment at the corrosion site of acetic acid concentration tower is acetic acid+chlo-ride ions.The enrichment of chloride ions in the tower accelerates the corrosion of acetic acid.Material upgrading and process corrosion control were suggested as the research direction for acetic acid concentration tower.