合庫與農銀的合併是國內首宗公股銀行的合併案，國內一些學者從銀行的的相關財務比率來探討本案是否有合併綜效。但是銀行的經營動能來自於分行，合併後分行是否能有效提升其經營績效，才是關係著合併綜效是否能持續發揮的關鍵。因此，本研究試圖比較兩家公股銀行合併後分行績效是否提升，來檢視合併的成果。 本研究係以合庫與農銀合併前後三年即民國92年至民國98年間的分行做為研究樣本，實證結果發現合併後分行的整體技術效率、純粹技術效率及規模技術效率均較合併前高，合庫端分行的整體技術效率、純粹技術效率及規模技術效率均較農銀端分行高，顯示合併確實有合併綜效效果。在各項影響分行經營績效的變數中，區域是影響分行經營績效的最主要因素，次要的影響變數是業務類型、城鄉、營業規模及壞帳率。 / The merger of Taiwan Corporative Bank (TCB) and Farmers Bank of China (FBC) was the first consolidation case of public owned banking industry in Taiwan. Many studies used financial ratios to analyze the consociation synergy of the merger.For banking industry, however, the branch offices' operatings are the major driving force for the bank. Therefore, the key factor to evaluate the success of the consolidation is to evaluate the performance change of branches after merger. This study tries to compare the branches performace change to evaluate the synergy effect of the consolidation on two public owned banks. The sample of the branches came from 3 years before and after TCB and FBC from 2003 to 2009. The study applies Data Enveloping Analysis (DEA) and grand frontier approaches to measure the trend of efficiency for overall technical efficiency(OTE), pure technical efficiency(PTE), and scale efficiency(SE). The empirical results reveal that the average OTE, PTE and SE of the branches after merger are higher than those of before merger, and the branches of TCB indicate better efficiencies than FBC, which implies that the consoliation indeed create a synergy effect. The branches location is the major factor that affect the efficiencies of the branches and other factors include the type of operating, city or rural area, the scale of the operating and the bad debt ratio.