Abstract: In this paper, the characteristics of focal precursors, field precursors of subsurface liquid before the moderately strong earthquakes and the remote precursors before the strong earthquakes are analyzed. The results show that the focal precursors of moderately strong events occurred 1-2 years before the moderately strong events, most of synchronous anomalies of major observational items occurred at the observational sites, the reverseor turning the anomalies might occur imminently before the moderately strong events and recovered after the events. Most of the field precursors are ex pressed as change of the short-termanomalies at a few observational sites rather than all the sites, while the field precursors of strong earthquakes occurred at a few observational sites, where only some observational items with good earth-quake-reflecting capacity showsynch ronous medium-termanomalies. The remote precursors of strong earthquakes (or earthquakeswarm) are mainly ex pressed as the precursory anomalies of few observational items with good earthquake-reflecting capacity. The cause of earthquake precursors is also preliminarily discussed.

Key words: Subsurface fluid, Moderately strong earthquake, Precursor, Xinjiangregion