To provide an exhaust purifying system and a method for controlling the exhaust purifying system that avoid occurrence of clogging, breakage, or the like of a reducing agent injection valve caused by the solidification of a reducing agent and prevent reduction in the efficiency of reducing agent recovery processing and exhaust gas purification.;An exhaust purifying system and a method for controlling the exhaust purifying system according to an aspect of the present invention is configured to detect the injection valve temperature of the reducing agent injection valve according to detection of turn-off of an ignition switch for stopping the internal combustion engine or detection of an injection stop of the reducing agent injection valve, whichever is earlier, calculate the waiting time until reducing agent recovery processing starts based on the injection valve temperature, and permits the reducing agent recovery processing under condition of the detection of turn-off of the ignition switch and an elapse of
