本研究係以民國81年1月1日至民國90年12月31日間曾從事併購行為之國內53家上市櫃公司為研究樣本，取其併購前後五年之財務資料，利用資料包落分析法計算其整體技術效率、純技術效率、規模效率值，再依據目標公司是否位於國內為併購類型的分類標準，探討併購活動與併購類型是否影響主併公司績效。 本研究實證結果如下： 一、在不考慮併購類型的情況下，併購前後對於整體技術效率、純技術效率與規模效率呈現不顯著的正向關係，表示併購後效率雖然有提升，但未達顯著水準。 二、在未區別併購前後的情況下，雖然併購類型對於整體技術效率與純技術效率均呈正向關係，與規模效率則呈負向關係，但三種效率值皆未達到統計上顯著水準，表示進行國內併購與跨國併購的主併公司在效率上沒有太大差異。 三、跨國併購後在整體技術效率、純技術效率與規模效率均呈現正向關係，並且在整體技術效率與純技術效率達到統計上顯著水準，表示「國際化網路」假說確實存在。 / In this research, we based on the companies that listed in Taiwan Security Exchange or the OTC which had domestic or foreign acquisitions over the period from 1992 to 2001. Using these firms’ five years financial data before and after acquisitions, we apply Data Envelopment Analysis to measure efficiency and compare the performance of firms following domestic or foreign acquisitions. The major research finding as follows. First, if we do not consider the type of acqusiontion, domestic or foreign, the results denote that there is no efficiency difference before or after acquisitions. Second, after we control before or after acquisitions, the results demonstrate that there is no efference difference between domestic and foreign acquisions. Third, after we control the cross effects between acquisition time and acquisition types, the results show that after foreign acquisitions the merger companies increase efficiency significantly, which confirms “Positive Multinational Network Hypothesis”.