A method for controlling the charging of packet data service includes: monitoring a number of event triggers; and when one of the event triggers is met, a Traffic Plane Function (TPF) requesting charging rules from a Charging Rule Function (CRF). In the preferred embodiments, the event triggers, which the TPF is required for request charging rules from the CRF according to are set by the CRF and then are provided to the TPF. Charging-relevant input information is provided in the request, based on which the CRF determines proper charging rules and sends the determined charging rules to the TPF. In this way, the timing that the TPF requests charging rules from the CRF becomes controllable, and redundant information caused by the unnecessary charging rule from the TPF becomes avoidable, which enables effective interaction between the TPF and the CRF and reasonable charging control of packet data service.