Regarding the collection of impact frequency data for open-pit down-the-hole drilling rigs, based on the drilling sound signal characteristics of the TAIYE-390-Ⅱ open-pit down-the-hole drilling rig, a sampling frequency of 6 kHz, which renders the impact waveforms most distinct, was determined to be advantageous. A method for collecting impact frequencies based on Hilbert transform, Variational Mode Decomposition (VMD), and Savitzky-Golay filtering was proposed, and an impact frequency collection system was developed. This system consists of three main parts: a digital microphone, a data acquisition card, and an industrial computer, which can achieve accurate collection and storage of impact frequencies. By conducting constant wind pressure and constant axial pressure drilling experiments, the reliability of the system was verified. Combined with borehole inspection experiments, the feasibility of identifying structural surfaces in rock formations using impact frequencies was analyzed. The results show that the impact frequency collection system can accurately extract real-time drilling impact frequencies, with an error controlled within 1 Hz, and it complies with the working characteristics of down-the-hole impactors. Meanwhile, the impact frequency exhibits a more pronounced response to rock structure, decreasing by 1 to 3 Hz when encountering various structural surfaces. The research findings have important theoretical significance and practical value in the collection of impact frequencies for down-the-hole drilling rigs and the identification of rock structural surfaces.