次級房貸風暴影響世界，是因爲資產證券化商品層層連結，金融全球化的資金自由移動，跨國證券投資交易大幅成長。銀行將取得的房貸債權委託特定金融機構證券化後分割販售，即爲不動產貸款抵押證券(MBS)，再結合其他債券包裝成擔保債權憑證(CDO)，銷售給下一層投資者，而可以把收到的資金再投資。房貸違約率快速增加，這筆損失就再向外層層擴散，由投資者承擔。本文的重點在探討美國次級房貸向外層層影響全球經濟的過程與影響。

Because of the property negotiable securities commodity layer upon layer links, the capital flows free by financial globalization and a lot grew in international securities deal, American sub-prime mortgage loan storm has influenced over the world. Banks entrust creditors' rights to certain financial institutions for securitization, and then divide them to sell. Furthermore, the Mortgage Backed Securities (MBS) pool the other bonds into Collateralized Debt Obligation (CDO), and then sell to next layer of investors. Through asset securitization, banks and financial institutions are able to recall funds for re-investment. However, when the rate of breaking mortgage loan rises, the loose extend into layer upon layer of investors all over the world. This study is to discuss the spread processes and influence of American sub-prime mortgage loan to the global economy.