近二、三十年來全球商品貿易的本質有很大的改變，尤其是產品的製造過程中，國際間垂直分工(vertically linked in international production)的程度越來越大，使得一個出口產品往往是經由多國階段不同的專業化分工形態所完成。根據Hummels, Ishii, and Yi (2001)的研究指出，自二次世異大戰以來垂直專業化貿易(vertical specialization in trade)的形態是造成全球貿易的成長多於所得成長的重要原因。所謂「垂直專業化貿易」是指一國自他國進口中間財做為該國產品的中間投入，經過加工和製造後，再將產品出口的貿易形態。本文分析台灣在民國70年到民國85年的垂直專業化貿易的程度及其對產業結構的影響。主要的結論如下：（1）歷年來垂直專業化的程度逐漸提高，由民國70年的48.32％不斷上升至85年的69.05％。這表示過去二十年來台灣在國際貿易上有相當的比例是朝著全球化的國際分工趨勢而演變。（2）工業部門佔整體產業的垂直專業化程度最高，比重超過90％。（3）實證結果顯示，關稅的逐年降低對垂直專業化貿易程度之增加有顯著的影響。這表示在透過關稅減讓的貿易自由化之下，生產的模式將逐漸趨向國際垂直專業化的分工形態。（4）產業結構、出口結構、進口結構、以及出口依賴程度也會影響垂直專業化貿易的程度。

　　　　　The nature of international trade changes dramatically in last few decades. Production sequence of a good involves several countries, with each country specializing in particular stages of good's production. These vertical linkages referring to imported inputs are used to produce goods that are then exported are called vertical specialization. Using the input-output table, this paper estimates Taiwan's vertical specialization in trade and the accompanying changes in the structure of industries from the selected years of 1964 to 1994 for country level and industry level. Key findings and implications are presented as follows. (1)The degree of total VS share of export was 48.32% in 1981 and 69.05% in 1996, a 42.9% increase in tow decades. This implies that a significant portion of international trade in the last tow decades has been following the trend of the world trade in moving toward the pattern of global production sharing. (2)Noteworthy is the manufacturing sector, whose VS share of exports has been steadily increasing and has accounted for more that 90% of the total VS shares of exports. (3)The effect of tariffs on trade verticality in our econometric analysis is statistically significant and negative. This suggests that trade liberalization through tariff reduction tends to modify the pattern of international production toward vertical specialization. (4)Sectors whose exports (and imports) constitute a higher proportion of total exports (total imports) in the economy, sectors whose export reliance index is smaller, and sectors whose relative size in the economy is smaller, tend to have a higher degree of VS-based trade.