The Xidatan buried fault is located in the north of Yinchuan basin and it is determined as one of buried faults in the active faults detection work of Shizuishan city. Based on the interpretation of seismic exploration for shallow layers, exploration of composite drilling section and core sample dating method are used to obtain some important data, such as depth of fault upper break- ing point, displacements and ages of key mark layer. The slip rates of Xidatan fault in different period of late Quaternary are finally estimated. The change of dip angle of key mark layer are found, and then, activity characteristics of Xidatan buried fault are discussed. The result shows that, with the deformation of the key mark layer, Xidatan fault ,which a low slip rate as 0. 024 mm/a, was a active fault in late Pleistocene and it＇s activity stop after 12 275±45 a B. P.. Not only offsets of the fault but also deformation of the key mark layer is characterized by intermittent activity. If considered these two changes as a whole, the minimum interval is 6 600 a and the maximum is 12 275 a.