Abstract: In order to detect the coal seam thickness of coal mining face,CT had been carried out in a suitable fre- quency by using Love-wave collected by transmission method. On the basis of negative correlation between velocity and coal seam thickness,and the channel wave dispersion curve of different coal seam thickness on base-step,and com- bined with coal seam thickness exposed by roadways,the velocity contour had finally been translated to coal seam thickness isoline. Coal seam thickness detection experiments had been taken in Yima coal area by above-mentioned technology. CT had been carried out in a frequency of 185 Hz,a velocity of 1 250 m / s had been predicted as the boundary of coal seam thickness in 1. 5 meters,then the contour of coal seam thickness in 1. 5 meters were drawn,and 5 areas where the coal seam thicknesses were less than 1. 5 meters had been circled. Predication results had been veri- fied in transformed roadways and mined out areas,and the forecast accuracy reached 84% . The safety and high effec- tive production had been guided by the technology in coalmines.