Abstract: In this paper, by using the methods of anomaly frequency accumulation and change velocity, we studied the time evolution character of hydrogeochemical group anomalies and the relationship between them and earthquake.The results, by using the method we may judge the nature of hydrogeochemical anomaly(as no earthquake, before earthquake and after earthquake), proved that the method has important practical sense to judge earthquake situation and predict earthquake.Moreover, by using the method we also may judge anomaly nature of other kinds of precursory observation items, it has vast developing prospect.