Embodiments of the present invention relate to a radio link reestablishment method and a controller. The method includes: if after sending downlink signaling or downlink data for designated times, a controller receives no corresponding acknowledgment returned by a user equipment in a cell dedicated channel state, or the controller receives a radio link failure indication message sent by a base station corresponding to the user equipment, the controller instructs the user equipment to re-search for a cell to trigger a cell update procedure, thereby improving reliability of a communications service, and ensuring normal running of the communications service.