The invention discloses a method and a device for selecting a charging mode and a communication system, which relate to communication technology, and can realize control on a user charging mode without affecting the use of user services. The method for selecting the charging mode provided by the embodiment of the invention comprises the following steps: acquiring the user information on a currentuser according to a received credit control request CCR; and selecting the charging mode of the current user according to configured filter conditions and the user information, wherein the filter conditions are stored in an on-line charging system.