Based　on　contagion　identification,　this　paper　studies　contagion　channels　and　mechanisms　of　the　U.S.　subprime　mortgage　crisis.　The　securities　markets　of　25　economies　are　divided　into　non-contagious　and　contagious　groups　by　using　the　adjusted　volatility　regression　model.　The　16　key　indicators　which　represent　the　five　contagion　channels　including　macroeconomic　fundamentals,　trade,　financial,　regional　and　debt　are　selected　to　conduct　both　sectional　and　panel　logit　regression.　The　sectional　model　finds　regional,　financial　and　debt　channels　determine　the　probability　of　contagion.　The　panel　model　shows　that　trade　and　financial　channel　are　main　transmission　channels.　Bank　capital　asset　ratios　are　significant　but　with　opposite　sign　in　both　models,　indicating　that　in　the　short　term,　although　with　high　capital　assets　rates　a　number　of　banks　bust　due　to　the　rapid　crisis　broken　but　in　the　long　term　the　higher　the　rates,　the　greater　to　resist　contagion.　©,　2014,　Systems　Engineering　Society　of　China.　All　right　reserved.