Abstract: In view of the prominent problem of the lack of detection methods for the roof rock strata of coal mine tunnels, which leads to the inability to systematically reveal the properties of the roof rock strata, a sonic logging system suitable for tunnel roof hole detection was developed and field tests were conducted. Acoustic signals from a 20 meter borehole were obtained and compared and analyzed with coring results and optical imaging. The research results indicate that: (1) an integrated device for water injection and hole sealing has been developed, which adjusts parameters such as hole sealing pressure and water injection pressure by changing the system unloading pressure, ensuring that the water level in the hole is always in a full hole state under the condition of hole sealing; A probe sealing push device has been developed, which has both axial and radial sealing functions, and can achieve continuous sliding of the acoustic probe in a liquid filled borehole, enabling continuous testing of acoustic data of the borehole wall and rock layers. (2) The full wave waveform of the rock layer in the roof drilling hole wall is divided into three parts according to the arrival time: longitudinal wave, transverse wave, and Stoneley wave. The transverse wave lags behind the longitudinal wave by 2-3 cycles and has a 180° phase reversal characteristic; In the case of sandstone roof, the measured borehole wall wave velocity ranges from 2750 m/s to 4000 m/s, which is basically consistent with the results of previous core lithology analysis. (3) Obtained acoustic imaging information of tunnel roof drilling, and compared it with the attenuation curve of reflected wave amplitude and optical imaging results, which showed high consistency among the three.