Online banking gradually becoming an important source of commercial banks' profits, it is of practical significance forthem to know the main contributors to online banking development. To help them better informed, this study made use of the Group Method of Data Handling approach to automatically screen various contributing factors to online banking business in an objective manner, and establish non-linear relationships between online banking business and its contributing factors. It was found that the primary contributing factors weregovernmental policy, e-commerce development, online-marketing and cyber security, with the policy factor and online-marketing having less to do with online banking business, while e-commerce development and security played vital roles. Moreover, between these factors and online banking, there werenon-linear relationships as well as linear ones. This conclusion could help customers better understand the contributors to online banking development, and assist commercial bank managers in better handling online banking business.