Load　frequency　spectrum　is　one　of　the　key　issues　to　study　Bridge＇s　fatigue　damage　caused　by　actual　traffic　loads.　For　the　expressway　bridges,　the　research　concerning　the　evaluation　method　of　the　reinforced　concrete　bridge＇s　fatigue　damage　based　on　the　data　taken　from　highway　toll　station＇s　weight　system　has　great　practical　significance.　In　this　study,　a　continuous　rigid　frame　bridge,　named　Xiabaishi　Bridge　with　span　arrangement　145+2x260+145　m　located　in　Shen-Hai　Expressway　was　selected　as　a　case　study;　the　fatigue　damage　caused　by　actual　traffic　loads　was　examined:　Firstly,　the　vehicle　records　that　passed　Xiabaishi　Bridge　from　all　toll　station　traffic　records　of　Fujian　province　during　the　period　from　January　to　February　in　2009　were　chosen　and　screened,　and　22　kinds　of　vehicle　models　were　obtained　after　statistical　analysis.　Then,　nine　classified　kinds　of　vehicle　models　were　determined,　and　their　frequencies　of　occurrence　obtained　based　on　Miner＇s　hypothesis　was　adopt　as　the　load　frequency　spectrum　for　fatigue　damage　analysis　of　the　Xiabaishi　Bridge.　It　is　concluded　that　6-axle　trucks　only　accounts　for　6%　of　all　vehicles　while　account　for　58.7%　of　total　fatigue　damage.　Therefore,　6-axle　trucks　are　the　vehicle　type　that　causes　most　fatigue　damage　of　the　bridge.