The embodiment of the invention provides an automatic identification and conversion method and device of stratum cycle and a storage medium. The method comprises the following steps that time-frequency analysis of seismic waveform is conducted to from a time-frequency spectrum; a waveform feature point sequence is extracted from a time-frequency waveform at a time-frequency spectrum center trace;a waveform feature point of the waveform feature point sequence is adopted as a seed point for time-frequency spectrum in-phase axis tracking to form an in-phase axis trend line; gradient of the in-phase axis trend line is determined; according to the gradient of the in-phase axis trend line, the waveform feature point sequence is converted into a stratum cycle feature point sequence; the stratumcycle feature point sequence is converted into a stratum cycle curve; and the stratum cycle curve is converted into a specified stratum cycle unit sequence. Efficiency and accuracy of stratum cycle identification and conversion can be improved.