An energy treatment system and a output control method thereof according to embodiments of the present invention perform treatment by energy supply in which ultrasonic energy and high frequency energy are combined, stop or suppress discharge by reducing the output of high frequency energy within a set period when a state in which discharge is likely to occur during treatment is detected, and change the output of ultrasonic energy. In addition, in order for a user to continue treatment without feeling uncomfortable and to ensure incision performance, each output is controlled so that the set period is as short as possible or is supplemented, and also, the set period expires, and control is performed so as to reduce the possibility of discharge even at the time of returning.