Offshore　bridges　may　suffer　from　chloride　ion　corrosion,　tsunami　wave　impact,　and　earthquake.　However,　the　coupling　effects　of　multiple　factors　have　not　been　fully　considered.　This　paper　studied　multiple　degradation　effects　on　the　seismic　performance　of　offshore　piers　considering　tsunami　wave　impact,　chloride　ion　corrosion,　and　their　interaction.　Firstly,　through　the　scale　model　test　of　tsunami　wave　flume,　the　wave　force　of　box　girder　structures　and　piers　under　different　tsunami　wave　conditions　is　measured.　Then,　according　to　the　corrosion　characteristics　of　coastal　chloride　salts　on　reinforced　concrete　bridge　piers,　the　corrosion　parameters　is　selected　by　Latin　hypercube　sampling,　and　the　influence　of　corrosion　expansion　and　cracking　of　bridge　pier　cover　on　the　chloride　ion　corrosion　process　is　considered　to　modify　the　degradation　model　of　corroded　reinforced　concrete　materials.　Finally,　the　wave　load　measured　by　the　test　is　converted　by　the　similarity　criterion　of　the　fluid　mechanic　test　and　loaded　into　the　ABAQUS　full-bridge　model,　and　the　pier　after　the　tsunami　wave　is　evaluated　by　the　pushover　analysis.　The　bearing　capacity　and　lateral　stiffness　of　the　corroded　pier　before　and　after　different　tsunami　waves　are　compared.　The　results　show　that　the　lateral　bearing　capacity　and　stiffness　of　bridge　piers　are,　respectively,　decreased　by　27.6%　and　6.2%　after　30　years　of　service.　Without　corrosion,　the　lateral　bearing　capacity　and　stiffness　of　piers　were,　respectively,　reduced　by　11.45%　and　10.6%　after　HXB-5　wave　impact.　After　30　years　of　service,　the　lateral　bearing　capacity　and　stiffness　of　bridge　piers　are,　respectively,　reduced　by　41.8%　and　22.5%　under　the　combined　action　of　corrosion　and　HXB-5　wave　impact.　It　is　found　that　the　coupling　effects　of　multiple　degradation　factors　were　more　significant　than　the　simple　superposition　ones.　Therefore,　the　coupling　effect　of　multiple　factors　should　be　considered　in　practical　engineering.