近年來，臺灣與中國大陸積極進行金融改革，開放外商銀行進入，但這樣的開放是否可以透過外資進入提升當地國銀行業的效率？而公股對銀行業的效率影響又如何？由於兩岸銀行業之成本函數不相同，故本文首先利用Battee and Coelli（1995）之隨機邊界法（stochastic frontier approach, SFA），分析外資、公股等股權結構及環境變數對銀行業成本效率之影響，之後利用Battese et al.（2004）的共同邊界法（metafrontier approach）進行兩岸銀行業成本效率之比較分析。本研究之實證結果發現：（1）外資銀行進入，對臺灣與中國大陸的銀行業效率的提升皆有顯著正面影響。（2）但公股部分，臺灣銀行公股主導的銀行有助於其效率的提升，然中國大陸則相反，公股主導的銀行反增加其成本無效率。（3）在共同邊界成本下，近年來中國大陸銀行業的技術效率、共同成本效率已逐漸相對臺灣銀行有優勢。

Taiwan and Mainland China are proactive in undergoing financial changes, and open the foreign bank to enter the local market. The concern in this study is to answer the question whether opening up the market through foreign bank entry can increase the banking efficiency and how ownership structure change affects the efficiency of domestic bank industry. Therefore, this paper uses stochastic frontier approach of Battese and Coelli (1995), and meta-frontier approach of Battese et al. (2004) to investigate the effects to banking efficiency due to the opening up their markets to foreign banks entry and the ownership structure changes. Our empirical results find that: (1) increase in foreign bank entry or investment can increase efficiency international competitiveness of host banks in both Taiwan and mainland China; (2) but the government shares has positive influence to bank efficiency in Taiwan, but negative influence to bank efficiency in mainland China; (3) the estimated metafrontier cost function shows that the technology gap ratio and meta-cost efficiency of mainland China's banking is higher than the one of Taiwan, bank industry in mainland China has a better performance than Taiwan.