In　order　to　explore　in　depth　the　significant　factors　affecting　the　traffic　risk　of　bridge　sections　of　freeway，this　paper　taking　traffic　order　index（TOI）as　dependent　variable，　and　identifies　the　relationship　between　TOI　and　traffic　characteristics，road　attributes，and　external　environment.　Based　on　the　safety　evaluation　model，the　Plots　of　individual　conditional　expectation　（ICE）were　applied　to　discover　the　contributing　factors　to　traffic　risk　of　bridge　sections　of　freeway.　The　results　indicate　that　compared　with　the　gradient　boosting　decision　tree　model，the　random　forest（RF）models　is　more　accurate　for　traffic　safety　risk　evaluation.　In　addition，among　the　influencing　factors，congestion　is　an　important　traffic　flow　factor　affecting　the　safety　risk　of　bridge　sections.　Under　low　visibility　and　adverse　weather　conditions，traffic　risks　are　higher.　The　upstream　and　downstream　of　the　river-crossing　bridge　are　considered　high-risk　corridors　in　the　bridge　sections　of　the　freeway.　This　paper　can　provide　new　ideas　and　methods　for　traffic　safety　risk　evaluation　and　discovery　of　contributing　factors　to　traffic　risks　of　bridge　sections，which　is　helpful　for　the　traffic　management　department　to　accurately　implement　management.　©　2022　Science　Press.　All　rights　reserved.