Abstract: The detonating cable fault detection methods are mostly of contact type and these methods have hidden danger and the detection efficiency is low. In order to solve the above problems, this paper presents a new method based on air coupled ultrasound for the detection of the broken and weak points,through the non-contact detection of the drug core of the detonating cable the broken and weak points could be quickly found. Experimental results show that the method can effectively improve the detection efficiency and precision of the real-time detection of the broken and weak Points.