The invention provides a single side soft absorption type automatic drilling robot which is applicable to operation such as hold drilling, reaming, dimpling and the like at wings and fuselage parts, and the machining for materials which are hard to machine such as titanium alloy (Ti) and composite materials (CPRF) is realized. The robot is fixed at an expected machining area by using a gas source provided by a vacuum generator and by using a vacuum chuck; and a soft track can adapt to different machining curves according to different curvature. The positioning of a drilled hole and the adjustment of the verticality of a drill bit are realized according to a drill plate. A pneumatic main shaft is adopted as the main shaft of the robot; and in combination of an ultrasonic vibration machining technology, the quality and efficiency of the machining are improved; the machining difficulty is reduced; the current detection at a feeding direction can be carried out in real time during the hole making process; and the protection and precise control for the machining process are realized.