Abstract: In order to study the influence of lift height on transient electromagnetic detection technology, a sensor device together with a test platform was built and the test plan was correspondingly designed. The results show that the effective lift height for test piece of thickness being 5 mm, 10 mm and 15 mm is 100 mm. The effective attenuation height of the received signal is constant. When the lift height is greater than 100 mm, the effective coverage of the sensor is verified to be 400 mm. For the experimental data of the thickness of the 20 mm test piece, the applicable range of the sensor is known. It is determined that the floating position of the transient electromagnetic sensor has no influence on the evaluation result. The test result provides reference value for the design of the non-excavation corrosion detector, the optimization of the pulsed eddy current probe and the corrosion evaluation accuracy in the actual working condition.