Abstract: In this study, the horizontal component of the 5th and the 45th seismic records of the SMART-1 array were selected. Firstly the lagged coherencies of seismic ground motion of station pairs with different separation distances were calculated. Then the influence of station distance on the fitting of parameters of the coherency function model was discussed, that is, there were obvious differences between the fitting results of the coherency function of a certain distance and the coherency functions of all different distances. In order to reduce this deviation, a method of quadratic regression on the fitting parameters of the coherency of different distances was proposed, and the Loh coherency function model was selected for verifying the method. Finally, the correction results of the fitting parameters based on the Loh coherency function model were given. The results show that the correction method proposed in this paper will greatly improve the fitting accuracy of the parameters in the coherence function model.