在全球化的影響之下，研發與創新已不再是先進國家所專屬的活動，跨國企業為了建立全球研發網絡，除了在母國從事研發活動外，亦會考量不同研發目的與需求之下，而在先進國家或開發中國家設立海外研發據點。本研究以民國93至96年製造業對外投資廠商為研究對象，以雙變數Probit模型 (Bivariate Probit Model) 來分析對外投資廠商之海內外研發活動決策因素與關聯性以及海外研發決策對國內研發決策之影響；接著考慮因技術水準不同所產生的產業異質性，探討高科技產業與非高科技產業廠商海內外研發活動關聯性之異同之處，以及隨著時間遞移，對外投資廠商之海外研發決策對國內研發決策是否有趨勢性的影響。 實證結果顯示全體製造業、高科技產業與非高科技產業廠商之海內外研發具高度相關性，但只有高科技產業廠商之海外研發決策對國內研發決策有顯著負向的影響。另外，全體製造業、高科技產業與非高科技產廠商之海外研發決策對國內研發決策，隨著時間遞移皆呈現顯著負向趨勢，代表以中、小企業為主體的台灣製造業之廠商，在有限的研發資金下，無法同時兼顧海內外研發活動之情況愈來愈明顯，於是對外投資廠商於國內或海外擇ㄧ地點從事研發的趨勢亦愈趨明顯。 Under the wave of globalization, innovation activities are no longer confined to the developed countries.. Currently, many multinational enterprises (MNEs) not only establish R&D center in home country, but also set up R&D labs oversea, with various considerations to choose the offshore R&D locations. In this study, we apply Bivariate probit model to the firm level data of Taiwanese manufacturing to investigate the relation between domestic and oversea R&D decisions, and their determinants. The heterogeneity between high-tech and non-high-tech industries is considered and a time trend variable is introduced to investigate if the impact of oversea R&D decision on domestic R&D decision expressed a traceable trend. According to our empirical result, the decisions of domestic and oversea R&D activities are highly correlated in the samples of whole Taiwan manufacturing, the high-tech and non-high-tech industries. Specifically, in the high-tech industry, the direct impact of oversea R&D decision is negative on domestic R&D decision. In addition, the negative impact of oversea R&D decision on domestic R&D decision increases as time passed , no matter in the samples of the whole manufacturing, or the high-tech , or the non-high-tech industries. These results imply that the small and medium-sized enterprises in Taiwan usually do not have that much bankrolls on innovation to support domestic and oversea R&D activities at the same time, thus they will tend to choose their R&D location between home country or oversea only.