Described herein is a method for processing an invalidation of a downlink data tunnel between networks. The method includes the following steps: (1) a core network user plane anchor receives an error indication of data tunnel sent from an access network device, (2) after deciding that the user plane corresponding to the error indication uses a One Tunnel technology, the core network user plane anchor notifies a relevant core network control plane to request recovering the downlink data tunnel, (3) the core network control plane recovers the downlink data tunnel and notifies the core network user plane anchor to update information of the user plane. In addition, a communication system and a communication device are also provided. The method, system, and device can improve the speed of recovering data transmission after the downlink data tunnel becomes invalid.