Based on the advantages of the wavelet to separate regional field and local anomalies in MATLAB environment， a high-precision regional-residual separation was finally realized． Analytical continuation and trend surface analysis are conventional methods for gravity anomaly separation． But the wavelet packet analysis in analyzing gravity data can make the gravity anomaly to be computed at a higher precision． In this paper，wavelet packet method is used to process gravity anomaly data obtained in Laos，and the separation result is good． Daubechies wavelet series has a higher precision in the wavelet packet．