On September 5, 2022, an M_S6.8 earthquake struck Luding County, Ganzi Prefecture, Sichuan Province. Slow earthquakes manifested as very low frequency earthquakes occurring in the source region before the Luding earthquake hold significant implications for understanding the source physical processes of the mainshock. This study employs the Hilbert transform and short-time Fourier transform (STFT) to detect very low frequency earthquakes preceding the mainshock, with preliminary analyses of their recording stations, spectral characteristics, and temporal features. The results indicate the following: (1) A total of 14 very low frequency earthquakes were detected before the mainshock, and their vertical and horizontal components could be effectively detected, with superior detection performance in the vertical component. (2) Events with large amplitudes and long durations were better identified using the Hilbert transform, whereas those with small amplitudes, short durations, and overlapping waveforms were effectively detected using STFT. (3) A total of 67.7% of the stations successfully recorded all events, demonstrating strong observational reliability. The very low frequency earthquakes exhibited distinct spectral peaks within a relatively low-frequency range (0.06-0.16 Hz), markedly differing from the frequency bands of natural earthquakes. The event with the largest amplitude occurred 18 h before the mainshock, followed by an increasing frequency of events accompanied by heightened small earthquake activity. This pattern may reflect a gradual release of crustal stress through very low frequency earthquakes and minor earthquakes until the occurrence of the mainshock.