Abstract: Based on two earthquake groups occurred in North China, the characteristic of precursory anomaly for earthquake group is analyzed. The characteristics of anomaly for earthquake group mainly are: (1) the temporal span of anomaly is large, and the anomaly, which behaves tendency anomaly, generally run through the whole earthquake group; (2) there are small fluctuations under the tendency background of the anomalies for earthquake group, which is new response for a single earthquake; (3) the figures that exists anomaly of earthquake group generally have large turning or kick before the beginning of a group; (4) there is usually correlativity between the anomalies of different approaches.