The invention relates to the machining field of drilling holes in hard and brittle materials, in particular to a laser and ultrasound combined type drilling system and a machining method thereof. According to the laser and ultrasound combined type drilling system, the hard and brittle materials can be protected, high-speed machining can be realized and locating can be accurate. The laser and ultrasound combined type drilling system mainly comprises a laser machining system, an ultrasonic machining system, a precision rotating and locating mechanism and an axis aligning system, wherein the laser machining system and the ultrasonic machining system are installed on the precision rotating and locating mechanism to regulate locating. The axis aligning system mainly comprises a locating panel, locking structures, a gravity center sensor, a distance sensor, an oriented adjusting structure, a movement adjusting base and a drive control device, and the locating panel is a thin supporting panel loading work-pieces to be machined. Through a combined drilling method, the hard and brittle work-pieces can be machined at high speed and high precision. The laser machining system and the ultrasonic machining system are adopted for combined machining procedures, and therefore pre-drilling can be carried out in advance, high-speed operation can be realized, the quality of the work-pieces can be protected, and the surface machining precision can be improved.