Abstract: The differences of multiple spans of multiple reflected wave during propagation and the variation of amplitude of reflected wave with propagation distance as well as the influences of the scanning step of the probe on the signal of the defect multiple reflected wave were analyzed for improving nondestructive testing rate of the spring flat steel. And then the defect location and quantitative method based on transverse wave multiple reflection and the probe scanning mode suitable for high efficiency detection were proposed, which provides a technical basis for industrial on-line detection of spring flat steel. The results show that the defects can be accurately evaluated based on the multiple reflected wave of transverse wave. It can be seen that, when using 5P8×12K1 transverse wave angle probe to detect a spring flat steel with 13 mm thickness, horizontal holes with 1 mm diameter and 10 mm length, 311 mm distance from the probe incident point can be detected, and the locating error of horizontal distance between horizontal hole and the probe incident point and depth is less than 3 mm. A defect quantitative method is proposed based on the refleced characteristics of different diameter horizontal holes. Combining the transverse wave multiple reflection method, the proposed scanning method can effectively and reliably detect spring flat steel.