A drilling process monitor (DPM) for ground characterization of weathered granite is presented. The monitor is portable and can be mounted on a hydraulic rotary drilling rig to record various drilling parameters in real time during normal subsurface in- vestigation. The identification method for dominative and subsidiary interfaces has been established. The study reveals that the monitored drilling parameters are dependent on geotechnical materials and can be further applied to characterize ground interfaces. The t-test between manual logging and DPM logging has been carried out. The results show that the DPM has high accuracy in inter- faces detection and well agreement with the manual logging. The findings show that the device and data analysis method are of po- tential application in subsurface drilling exploration in weathered granites. It also seems to have prospective uses in the determination of orebody boundary as well as in the detection of geohazards. The monitor is portable and can be mounted on a hydraulic rotary drilling rig to record various drilling parameters in real time during normal subsurface in- vestigation. The identification method for dominative The study reveals that the monitored drilling parameters are dependent on geotechnical materials and can be further applied to characterize ground interfaces. The t-test between manual logging and DPM logging has been carried out. The results show that the DPM has high accuracy in inter-faces detection and well agreement with the manual logging. The findings show that the device and data analysis method are of po- tential application in subsurface drilling exploration in weathered granites. It also seems to have prospective uses in the the determination of orebody boundary as well as in the detection of geohazards.