The effect of the grouted length of mining cable anchor on the attenuation and group velocity of ultrasonic longitudinal guided wave mode L(0,1) is investigated experimentally. Firstly, propagation characteristics of ultrasonic longitudinal guided wave in mining cable anchor without grout are analyzed through the mode’s dispersion curves of steel wire that simplifies to be thin rod. Then, piezoelectric element of thickness vibration mode is used to carry out through-transmission experiment in cement grouted mining cable anchor, and the amplitudes of L(0,1) mode are acquired in the frequency range of 20-500kHz. The piezoelectric element’s most suitable excitation frequency for guided wave inspection of the cement grouted mining cable anchor is confirmed to be 280kHz. Based on this result, the attenuation and group velocity variation characteristics of L(0,1) mode at several frequencies near 280kHz are studied in mining cable anchor along with the increase of the grouted length. Finally, the through-transmission experiments are carried out in resin grouted mining cable anchor, the experimental results meet those obtained in the cement grouted mining cable anchors. These experiments provide the foundation for the length measurement of grouted mining cable anchors by using ultrasonic longitudinal guided waves.