Abstract: An MS 4. 9 earthquake occurred in Haiyuan County in Ningxia Hui Autonomous Region on July 29, 1998. Before the earthquake, the seismological Bureau of Ningxia Hui Autonomo us Region judged the tendency, medium-term and impending earthquake prediction to a certain extent. Guyuan Seismic Station of Ningxia Seismological Bureau and Guyuan Administrative Office of Ningxia Region have made explicit impending earthquake prediction. In this paper, the features of earthquake sequence, seismogenic structure and the evidence on which we have made our post seismic tendency judgement have been introduced. The evolutional course of precursory anomalies has been analyzed. Especially the discussion has been made on the analytical consideration regarding the impending earthquake anomalies, finally on the prediction succession and problems existed.

Key words: Earthquake Prediction, Seismicity, Precursory anomaly, Ningxia Haiyuan