A method and a system for providing a charging model, a method for charging, and a charging management system, which perform charging model selection or charging by means of loading charging plug-ins corresponding to different charging models. A charging management system is also provided. According to the invention, the charging plug-ins that provide charging models are independent of the charging management system per se, and the charging management system may obtain corresponding contents from the charging plug-ins via standard interfaces. Therefore, it is unnecessary to upgrade an existing charging management system when adding a new charging model, thus simplifying and speeding up development and deployment of new charging models, making development of charging models completely open, and speeding up diversification of data service charging models.