Abstract: The anomaly features of hydroehemieal components appeared before earthquakes consist of multiple forms,uneven amplitudes and complieated variations of the forms and amplitudes.To reveal the essence of the complexity,the experiments on hydrochemic model are carried out. The results indieate that the regularity of pulse hydroehemi-cal anomaly migration in the aquifer system is rather complicated. With increase of the migration distance,the information amplitude attenuates obviously,and even the anomaly forms are changed. These features of variation are also related with the stress state that the aquifer has been situated in.

Key words: Seismic hydroehemieal anomaly, Hydrodynamic model, Experimental study