In　recent　years　the　engineering　disasters,　especially　those　occurred　to　large-scale　public　projects　cause　enormous　economic-losses　and　negative　social　influence.　The　large-scale　public　projects　involved　numbers　of　participants　and　complicated　procedures,　which　make　the　risk　control　become　a　complicated　problem.　There　is　should　be　an　ew　method　to　do　with　the　modern　engineering＇s　risk　manage　requirement.　However　so　profound　influence　was　caused　by　the　traditional　ideas　and　so　many　multiple　benefits　were　interlaced　in　the　open　life-cycle　processes　of　major　public　construction　projects.　These　induced　some　construct　stages　and　participants　become　risk　control　blind　spots.　Thereby　the　high-efficient　risk　management　system　should　get　the　help　from　the　third-party,　which　is　independent　of　any　projects　participants,　to　intervene　in　major　public　construction　projects＇　life-cycle　risk　management.　The　third-party　is　which　called　forensic　engineering.　In　this　paper　the　idea　of　life-cycle　risk　management　was　put　forward　based　on　the　engineering　operation　processes　in　all　life-cycle,　the　stages　risks　and　duties　of　modern　engineers　were　analyzed,　the　conception　of　forensic　engineering　was　introduced,　and　how　the　forensic　perfect　to　the　risk　management　mechanism　was　explained.