The increasing utilization of titanium alloys in marine environments makes their microbiologically influenced corrosion study a timely matter.This work demonstrated that the corrosion of Ti-6Al-4V alloy was accelerated by a marine bacterium Shewanella algae in 2216E medium with different Cl level.Various electrochemical,pitting morphology and passive film analyses demonstrated that S.algae weakened the passive film,which made Cl-more aggressive.The synergy of those two factors caused considerable corrosion acceleration of the titanium alloy,leading to a maximum pit depth of 3.2 μm and corrosion current density of 26.5 nA cm-2 in 2216E medium with 3.50 ％ (w/w) Cl-.