Abstract: In order to further study the quantitative algorithm of buried metal pipeline corrosion, the decay law of TEM detection signal is analyzed firstly, and then a test bench is built to change the obtained induced voltage signal from Cartesian coordinate system to double logarithm coordinate system, and the attenuation slope is extracted as the characteristic value through the function y=2. 589 5x^{-0. 439} to get the mathematical model of wall thickness and decay rate. Finally, other steel samples were selected to verify the correctness of the mathematical model. The results show that the detection method can be effectively applied to the metal pipe wall thickness detection with a wide range of detection, and the wall thickness calculation error is not more than 5%, and is not affected by the lifting height. It provides a theoretical basis for the sensor design, optimization and function expansion of nondestructive testing technology.