企業內貿易效果之重要性，可增加公司的銷售總額，降低母國對地主國貿易順差，減少國際間摩擦問題。企業內貿易是母公司在地主國設立子公司，對子公司技術移轉，增加母子公司間之購買與銷售，提高母國與地主國之貿易總額。由於企業內貿易可運用：(1)輸出代替效果；(2)逆輸入效果；(3)輸出誘發效果；(4)輸入轉換效果，對地主國生產技術提升，增加就業率、增加稅收，也增加外銷，擴大國際市場之貢獻；對母國也增加外銷總額，降低貿易順差，減少國際間貿易摩擦之問題，也增加母國就業機會提高國際市場競爭力，母國經濟發展。企業經濟發展很多要素中，銷售總額的增加最重要，而銷售總額的增加策略中，以企業內貿易效果策略最值得研究。而銷售總額又深受關稅高低的影響。本研究是以我國企業有對大陸投資子公司為調查對象，以製造業為研究產業。網路郵件公司實地拜訪加上郵寄問券為主要收集樣本方式。共寄出500份，回收計334份，回收率達67%，其中36封為無效問券，實際可用問券為298封，而有效回收率為60%。研究結果發現，大陸與台灣之間的企業內貿易效果，深受ECFA的影響，況且對台灣外銷的貿易總額的增加，台灣企業的發展，國家經濟發展都有很大的影響。實證調查結果發現，自從ECFA的簽定，台灣企業對大陸有86%輸出大幅增加呈現台灣產品在大陸有高度的競爭力，回銷台灣也有83%在台灣市場與外來投資企業的產品有高度的競爭力，台灣有83%高科技中間材與零件，支援在大陸子公司之需求。有82%企業肯定對台灣經濟規模生產利益有高度技術之利。有85%企業認為肯定能穩定子公司在大陸市場之高度競爭力。有86%認為ECFA降低關稅企業獲利確實較高。有81%企業肯定對大陸有增加銷售總額。83%肯定確有提高長期利益。82%確實增加大陸市場的佔有率，70%確實獲得外來投資技術移轉增加，80%企業肯定可高度引進外來投資獲得中間材、零件等高科技技術可供大陸子公司需求。83%企業期待ECFA簽定內容更增加外來投資高科技技術移轉之意願，對台灣經濟發展有利，企業技術提升有利，青年就業機會提升。台灣大學生己高達98%，國民性勤勉獲世界經濟評估肯定，台灣未來是生產高科技中間材、零件的好地方。從台灣提供中間材零件經ECFA免稅給大陸子公司組合為成品，利用東協十一國，從大陸免稅外銷東協十國，並以經濟規模生產成本降低之利，從大陸外銷全世界市場，先進國企業對台灣投資高科技技術移轉，台灣是生產高科技中間材、零件的寶島，經濟發展、人民幸福。

The importance of internal quality and efficiency, can increase the company’s total sales, reduce the trade surplus of the home country against the landlord, reduce international friction. Intraindustry trade is the parent company setting up a subsidiary in the landlord country, subsidiary technology transfer, increase purchase and sales between parent and subsidiary companies. Increase the total trade between the home country and the landlord. Enterprise quality and easy to use 1. Output replacement effect 2. Inverse input effect 3. Output evoked effect 4. Input conversion effect, Improvement of production technology in the landlord, Increase employment rate. To increase taxes, Increase export, expanding the contribution of the international market; Home country also increased total export sales, reduce trade surplus, reduce the problem of international trade friction, increase employment opportunities in home countries and increase competitiveness in international markets, home country economic development. Among the elements of enterprise economic development, the increase in total sales is most important, Increase in sales total strategy, the most important strategy for enterprise internal quality and efficiency is worth studying. The total sales volume is deeply affected by the high and low tariffs. This study is based on the fact that Chinese companies have investment subsidiaries in mainland China, Manufacturing industry as research industry. Internet mail and Company visit and Mailing coupons as the main method of collecting samples, sample statistics. A total of 500 copies were sent, 334 parts of recycling, recovery rate of 67%, 36 of them were invalid questionnaires, the actual available coupons are 298, The effective recovery rate is 60%. The findings found, the effect of intra-industry trade between the mainland and Taiwan, deeply affected by ECFA, increase in total trade in Taiwan’s exports, national economic development has a great impact. Empirical investigation found, ECFA signing, taiwanese companies have a 86% increase in exports to the mainland, showing that Taiwanese products are highly competitive on the mainland. 83% of the products sold back to Taiwan are highly competitive with the products of foreign investment companies in Taiwan, Taiwan has 83% high-tech intermediate materials and parts, support the needs of mainland subsidiaries. 82% of companies are sure to have a high degree of technical interest in Taiwan’s economies of scale. 85% of companies believe that they can stabilize the high competitiveness of their subsidiaries in the mainland market. 86% think that ECFA’s tariff reduction companies are indeed higher. 81% of companies are sure to increase their total sales to the mainland. 83% certainly does improve long-term benefits. 82% does increase the market share in the mainland. 70% did receive an increase in foreign investment technology transfer. 80% of enterprises are sure to be able to introduce foreign investment to obtain intermediate materials, High-tech technologies such as parts can be used by mainland subsidiaries. 83% of enterprises expect ECFA to sign content to increase the willingness of foreign investment in high-tech technology transfer, conducive to Taiwan’s economic development, enterprise technology improvement, youth employment opportunities have increased. Taiwan’s college students have reached 98%, national sexual diligence affirmed by the world economic assessment, Taiwan’s future is a good place to produce high-tech parts. Providing parts from Taiwan via ECFA taxfree to mainland subsidiaries to form finished products, using the ASEAN 11 countries, tax-free export from the mainland, and the economic scale of production costs reduced, from the mainland to the world market, advanced state enterprises invest in high-tech technology transfer to Taiwan, Taiwan is a country that produces hightech parts, economic development, people are happy.