Abstract: The accuracy of reservoir prediction affects the economy of oil and gas exploration and development, and the low-frequency model method is one of the effective methods to improve the prediction accuracy of reservoir inversion under complex geological background. In order to remove the influence of special geological interfaces in the study area on reservoir inversion, the authors in this paper put forward a low-frequency model construction method to suppress the side-lobe interference of seismic data caused by strong reflection in limestone fracture-cave reservoir. Based on the seismic data obtained from the forward wave equation algorithm, and the low-frequency model is iterated for inversion and the side-lobe interference is gradually suppressed, which finally makes the inversion to be consistent with the geological model. The low-frequency model iteration method proposed in this paper is suitable for the fine characterization of fracture-vuggy carbonate reservoir, and provides reasonable elastic parameters for quantitative interpretation of reservoir, which has strong practical significance in the prediction of Ordovician fracture-vuggy reservoir.