Abstract: A billing method, and a billing system and a bill cycle cut off module which may be used in implementing the method, are provided. The method includes receiving an online billing message and carrying out preprocessing for the message, wherein the online billing message includes user identification information and billing information. The message further includes executing an online bill cycle cut off operation after determining that the bill cycle cut off operation is required to be triggered for an account related to the user identification information, obtaining a result of the bill cycle cut off, and carrying out a rating and billing operation according to the billing information so as to complete billing. The provided method can be applied to implement a real-time online bill cycle cut off and avoid loss resulted from out-of-time bill cycle cut off.