A system and method for detecting an air leak in a commercial vehicle can detect an air leaked portion of the commercial vehicle using ultrasonic signals measured by a plurality of measurement sensors. The system includes a detection unit for measuring a plurality of ultrasonic signals generated in the commercial vehicle through the plurality of measurement sensors, confirming a position and size of a leak portion where air is leaked based on the plurality of ultrasonic signals to generate sensing data, and generating a photographed image by photographing the commercial vehicle, a management unit for generating a transformed image using a reference value from the sensing data, and a synthesized image by synthesizing the transformed image and the photographed image, and a display unit displaying the synthesized image.