1. A method for provisioning and installing event triggers, which is applied to an evolved packet system, comprising: a policy and charging rules function entity (PCRF) provisioning event triggers to a bearer binding and event reporting function entity (BBERF) based on gateway control session level; after receiving the provisioned event triggers, the BBERF installing or updating the event triggers; wherein the event triggers comprise all event triggers of all IP connectivity access network sessions (IP-CAN sessions) of a user equipment, which share one gateway control session.