Understanding the impacts of new technology and innovations on the banking sector is important and of growing interest. However, there is limited research on the detailed channels of the impacts, and consequently, the evaluations for the aggregate welfare impacts. We contribute both empirically and quantitatively. We construct a new data set for Chinese banks. We ffnd banking innovations can improve efficiency, and mostly reduce non-interest costs but not so much on deposit rates. We show the ffnding is quite robust under a battery of checks. In a new structural, quantitative model, banks have heterogeneous capital, decide innovation investment and also risky lending, face regulations on the capital requirement and have limited liability. When aggregate new technology improves, it can reduce financial intermediation costs and social deadweight loss; however, it will also change the bank’s risk consideration and increases moral hazard when the cost is largely reduced. We also find several other new implications for R&D investment credit policy and Capital Requirement policy (CAR).