當前，中國大陸高科技業之生產品質和複製技術不斷升級，而兩岸高科技產品亦皆以亞洲最大經濟體日本為主要外銷市場之一，引發台商高科技業赴中國大陸投資生產是否會造成台灣高科技產品在日本市佔率被中國大陸取代的疑慮。本文採融合時間序列與橫剖面的模式(pooling model)，解析2000年～2006年之台商高科技業大陸投資累計比重與台灣高科技產品於日本市佔率的資料，實證結果顯示：台商高科技業赴中國大陸投資，並未使台灣整體高科技產品於日本的市佔率遭受中國大陸的競爭威脅。 Today, the manufacturing quality and replication ability of high tech products or materials in China is continuously improving. And Japan, the largest economy entity in Asia, is still the main market for both China & Taiwan to export the high tech products. Therefore, it is a great concern for Taiwan's market share in Japan if Taiwanese high tech companies continue to invest in manufacturing in China. This present paper adopted pooling model to analyze Taiwanese high tech firms' investment in China vs. their market share in Japan over the years of 2000~2006. And the result showed: the investment of Taiwanese high tech industries in China has no significant impact on their market share in Japan due to the competition from China.