Abstract: Aiming at crack detection of gas pipeline, an electromagnetic acoustic crack inspecting instrument of gas pipeline was developed. The high-power pulse electrical source, amplifying and receiving circuit, data sampling and compressing circuit and data analysis software were consisted. Crack detection experiments on gas pipe showed that the EMAT detection tool had high crack detection sensitivity, which could detect SCC cracks larger than 20 millimeters in length and 1 millimeter in depth.