A method and apparatus for controlling traffic of multiprocessor system or multi-core system is provided. The traffic control apparatus of a multiprocessor system according to the present invention includes a request handler for processing a traffic request of a first processor, and a Quality of Service (QoS) manager for receiving a QoS guaranty start instruction for a second processor from the multiprocessor system, and for transmitting, when traffic of the second processor is detected, a traffic adjustment signal to the request handler. The request handler adjusts the traffic of the first processor according to the received traffic adjustment signal. The traffic control method and apparatus of the present invention is capable of adjusting the required bandwidths of individual technologies and guaranteeing the real-timeness in the multiprocessor system or multi-core system.