如今世界貿易的型態大多以中間財貿易為主，這些中間財貿易，來自於國與國之間的委外代工，中間財或者零組件透過貿易的方式運送回母國組裝。然而Melitz(2003)指出生產力差異是新貿易理論重要的議題，也就是說，研究今日的委外代工行為，必須考慮廠商之間生產力的差異，而本文就是以此點當作立論的依據，進行模型分析。 　　因為異質生產力的因素，使得每一家廠商的邊際生產力皆不相同，於是中間財委外代的程度亦不相同。並且，考慮委外代工產生的固定成本，生產力對於委外代工程度的影響關係曲線呈現凹性，這使得工資水準和委外代工程度的關係呈現不確定的現象。 　　我們將產業的類型區分為高中間財依存度廠商，例如製造產業就是屬於這類型；以及高最終財依存度廠商，例如高科技產業屬於這類型。在高中間財依存度的產業中，開放海外生產，會使得產業的平均工資上漲，壓縮良好的工作，擴張劣等工作，均衡失業率上升。當開放海外生產，高最終財部門依存度產業中，國內的平均工資與失業率變化是不確定的。 / Most of the types of world trade today are dominated by intermediate trade, which are derived from outsourcing or offshoring. Melitz (2003) pointed out that the difference in productivity is an important issue in the new trade theory, that is, the study of today's outsourcing foundry behavior, we must consider the difference between the productivity of manufacturers, and this article is based on this point as a basis, Carry out model analysis. Because the heterogeneity of productivity factors, making each company's marginal productivity are not the same, so the level of the middle finance committee is not the same. Moreover, considering the fixed costs generated by the outsourcing of foundry, the relationship between the productivity and the degree of subordinate foundry is concave, which makes the relationship between the wage level and the degree of outsourcing found an uncertain phenomenon. We classify the types of industries into Manufacturing and Headquarter industry. In Manufacturing industries, offshoring will make the industry's average wage rise, a good job compression, expansion of poor work, increases unemployment rate. However, under Headquarter industry, the domestic average wage and unemployment rate changes will be uncertain, if they decide offshoring.