The invention provides a method for realizing the uninterrupted communication when the trunk gateway disaster tolerance occurs, as well as a system and media gateways thereof. The method comprises the following steps: after a first media gateway detects that a first link between the first media gateway and a first soft switch device is disconnected, the first media gateway can provide protection for the existing speech channel of the trunk gateway users and send the transmission-prohibited message to the end office; and after the end office receives the transmission-prohibited message, all the recent incoming calls are routed to a second media gateway. According to the method, the reliability and the disaster tolerance capacity of the network system can be improved, and the satisfaction degree of clients can be enhanced.