Embodiments of the present invention relate to the field of communications technologies, and provide a complex event processing method, apparatus, and system, so that when complex event processing is performed, a system requiring a synchronous response provides a synchronous response externally and avoids information flooding. A solution provided by the present invention includes: receiving an input event sent by an event source, where the input event includes an identifier of an object and an event type; acquiring, according to a preset database, M mode rules corresponding to the event type; performing mode matching between the input event and the M mode rules separately to acquire N output events; and if N is greater than or equal to 1, sending at least one piece of event information to a real-time decision apparatus, where each piece of the event information includes Q output events and indication information.