The Jurassic strata are weakly cemented with low-strength and low-density characteristics. The density differences between the coal seams and the surrounding rocks are not as big as the Permian and Triassic strata. The reconstruction equation for acoustic log needs to be established because traditional reconstruction equations are not suitable anymore. This research uses the logs of a mine in the Ordos basin to explore the reconstruction method. Firstly, a multi-scale wavelet transformation and histogram calibration were used to preprocess the logs, reducing the noise and improving the consistency. Then, the relationship between density and acoustic logs in the Jurassic strata was estimated. The correlation coefficient between the measured and the reconstructed acoustic logs is high, indicating high reliability. Finally, the reconstructed logs obtained by this method were compared with the results of the traditional Gardner's formula. The results showed that the reconstructed log fits the measured results better and the traditional approach. The improvement can serve seismic interpretation and inversion better and ensure the safe mining of coal mines.