A method and a system of realizing event detection are provided, which detect a status of an Internet Protocol (IP) connectivity access network (IP-CAN) bearer corresponding to a policy and charging control (PCC) rule by binding an Event-Trigger parameter to the PCC rule, thereby realizing small-granularity detection for the specific PCC rule and reducing the load of the system. Furthermore, a status of the IP-CAN bearer or an IP flow is realized by binding the Event-Trigger parameter to an IP-CAN identifier (ID) or an IP flow ID, so as to avoid the problem about too large granularity of the binding of event detection and IP-CAN session and reduce the burden of the IP-CAN bearer detection and message exchange.