By creating credits commercial banks contribute to the national economy and their branches are the catalysts of depositing, lending, and other associated activities. To comprehend the efficiency of commercial banks their branches must be brought under the microscope. The purpose of this chapter is to analyze the comparative efficiency of the bank branches from a micro point of view by introducing environmental changes. Firstly, we utilize Data Envelopment Analysis (DEA) to micro-analyze 18 bank branches of a Chinese commercial bank. Secondly, we decompose the effectiveness into efficiency and productivity to estimate the bank branches’ relative efficiency and productivity. To add, we also examine overall productivity along with average efficiency that assists in understanding each staff’s performance; this is a rarely investigated territory. Thirdly, we employ operating environment factors—a novel approach—with three dimensions (business conditions, competitiveness, and future development) to further detect and rank bank branches efficiency. We found that some branches performed efficiently (inefficiently) even in lower (higher) external environments; hence, locations and individual performance are vital influencers of bank branches’ efficiency. We recommend practical measures to improve the efficiency of inefficient branches in the areas of expense, revenue, and management; this will be beneficial for any commercial bank’s policy-making efforts.