Abstract: In order to make ultrasonic nondestructive testing technology can be better applied in the detection of support anchor bolt, the theoretical analysis and laboratory testing methods are used to study high-frequency guided wave propagation in the anchor bolt and free bolt. Among the guided wave frequency range which is between 1 and 15 MHz, frequency swept are carried out for anchor bolts with different anchorage quality, average amplitude ratio curve which varies with different frequency is worked out from the testing results. The ratio coincides with the theoretical attenuation dispersion curves.