介绍了超声导波的频散特性和输气管道腐蚀检测设备的构成，依据管道中导波的T(0,1)模态的非频散特性对低频段(70 kHz以下)反射回波信号进行了动态频率分析。结果表明：该分析方法能够清晰辨别管道特征信号，可以精确定位腐蚀缺陷的位置。但是，由于回波信号的叠加，与较大三通管位于同一截面的腐蚀缺陷信号难以识别。

As a new non-destructive detection mean, ultrasonic guided-wave technology is more and more widely used in pipeline inspection. The detection devices of ultrasonic guided waves and dispersive characteristics are introduced briefly. Based on the non-dispersion of T(0,1) mode, the reflected signals are analyzed with dynamic frequency in low frequency range(below 70 kHz) . The inspecting results show that the method can clearly identify the feature signals of pipeline and find out the accurate location of corrosion defect. Because of the superposition of reflected signals, the corrosion defects which are in the same section of asymmetric characteristics in pipeline are however difficult to distinguish.