Fiber　reinforced　polymer　(FRP)　bars　are　being　widely　used　in　civil　engineering　applications　to　replace　steel　bars　due　to　their　excellent　durability.　Existing　research　on　the　durability　of　FRP　bars　mainly　focuses　on　glass　fiber　reinforced　polymer　(GFRP)　and　basalt　fiber　reinforced　polymer　(BFRP)　bars.　Different　conclusions　have　been　drawn　due　to　differences　in　fibers,　resins,　fiber　volume　fractions,　solution　concentrations,　and　aging　temperatures　adopted　by　researchers.　Some　results　are　even　contradictory,　especially　between　relatively　recent　and　previous　studies.　In　this　paper,　data　of　557　experiments　on　tensile　strength　and　elastic　modulus　of　GFRP　and　BFRP　bars　exposed　to　different　harsh　environments　were　collected　from　existing　literature,　and　the　durability　of　GFRP　and　BFRP　bars　in　water,　acid,　salt,　and　alkali　solution　were　investigated.　Different　influence　factors　were　considered　including　the　matrix　type,　fiber　volume　fraction　and　exposure　temperature,　etc.　Furthermore,　a　new　prediction　model　for　the　long-term　performance　of　FRP　bars　was　developed　based　on　an　existing　model　and　the　data　collected　in　this　paper.　The　tensile　strength　of　GFRP　and　BFRP　bars　degenerated　faster　in　alkali,　and　water　environments,　followed　by　acid　solution,　and　had　the　best　durability　in　salt　solution.　Except　the　water　solution,　GFRP　bars　showed　better　corrosion　resistance　than　BFRP　bars　in　the　alkali,　salt,　and　acid　solutions.　The　new　prediction　is　simple　in　form　and　clear　in　the　physical　meaning　and　could　be　considered　for　both　GFRP　and　BFRP　bars.