Abstract: Based upon data for the Haicheng earthquake and the field investigations the further study is made for the temporal and spatial change of macroscopic field of precursors,the temporal correlation of the developing anomalies and the relation of their spatial distribution with the active faults.Described here are such aspects as fluctuations shown by macroscopic anomalies during the preparation of an impending earthquake,distributions characterized by the closely spaced belts and their inhomogeneity and migration.Building up and strenthening of stresses in the preparation of an impending shock may vary with time,spatially concentrated to various points in a stress field.With the comparision of the fluctuations in rapidly developing anomalies prior to occurrence of an earthquake,the time scale is excplored for predicting a major impending shock. The possible sites for future shocks are discussed on the basis of the spatial distribution of crossbelt anomalies,which is characterized by their migrating to epicenters from the outer.Finally,a few mechanisms are preliminarily investigated for the generation of main macroscopic anomalies.