This paper studies the effect of interbank business on the bank efficiency by using Tobit modelWe use 16 listed Chinese commercial banks data from 2005 to 2013 as sample to estimate the bank efficiency by the Stochastic Frontier Approach，and differentiates the distinct impacts of interbank business according to the bank scales and time periodsIn full sample，the development of interbank business has both improved both the cost efficiency and the profit efficiencyHowever，both of the impact of interbank assets and interbank liabilities on efficiency are nonsignificant during 2005—2009After 2010，the interbank liabilities have a significant positive effect on the bank efficiencyFor the large stateowned banks，the development on interbank business has contributed great improvement to efficiency throughout the whole sample periodFor the jointequity commercial banks，both interbank assets and liabilities have limited impacts on efficiency during 2005 and 2009，and the interbank liabilities improved the efficiency significantly after 2010

本文采用Tobit面板模型，选取了2005—2013年中国16家上市商业银行为样本，研究同业业务发展对银行效率的影响。笔者通过随机前沿法（SFA）估计出银行的成本效率和盈利效率。从全样本的回归结果来看，银行发展同业业务对成本效率和盈利效率都有提升，但在不同时期和对不同类型的银行，影响效果存在差异。2005—2009年，无论是同业资产或同业负债业务对银行成本效率、盈利效率的提升作用都有限。2010年之后，同业负债对银行效率的提高有显著正向作用。不同规模的银行同业业务发展对效率的影响也不同。大型银行在2009年前后同业业务的发展对效率提升起到了较大的贡献作用。中小型商业银行在2005—2009年，无论是同业资产或同业负债业务都对银行成本效率、盈利效率提升作用有限。而在2010年之后，同业负债业务显著提高了银行的效率。