The invention provides a BRT signal priority control method for a large four-way roundabout, which belongs to the technical field of intelligent traffic control. A road medium-sized BRT exclusive lanecrosses a center island. A BRT bus stop and supporting stereo cross-street facilities are arranged in the exit direction of the exclusive lane. Two crosswalks are arranged in the enter direction andexit direction of non-exclusive lanes in a malposition manner. According to the invention, in order to reduce the delay of BRT vehicles and efficiently serve conventional vehicles, five conventional vehicle phases, one BRT phase and two pedestrian phases are used to establish five kinds of passage right distribution states switched in a certain sequence; four types of BRT vehicle detectors and twotypes of conventional vehicle detectors are arranged; a number of traffic event management passage right distribution states are defined; signal priority modes such as green light extension, green light early start-up and phase insertion are supported; continuous traffic demand of conventional vehicles can be perceived and satisfied; BRT vehicles can acquire desired preferential passage; and thelandscape value of the roundabout is retained to a large extent.