Abstract: Acording to changes of seismic activity parameters and using actual observation data,the author has analyzed the changes of the seismic activity parameters in Hebei Province and its adjacent regions before the Zhangbei M_S 6.2 earthquake and the attenuation characteristic of its sequence.The result shows that the seismic activity parameters in the area of 100 km around the focal zone and large range showed long-term,mid-term and short-term andomalous changes before the Zhangbei M_S 6.2 earthquake.Before the strong after shocks of the Zhangbei M_S 6.2 earthquake,the seismic activity parameters showed short-term and imminent changes.