On the basis of the absolute and relative gravity observations in North China, spatial dynamic variation results of regional gravity field are obtained. Multi-scale decomposition technique are used to separate anomalies at different depths, and give some explanation to gravity variations at different time space scales. Gravity variation trends in North China are improved. Based on this result, the analysis of wavelet power spectrum, the image of the depth of wavelet approximation and detail are obtained. The results obtained are of scientific significance to deeply understand the potential seismic rick in North China for gravity variations in different time space scales.