Abstract: The short-term and impending earthquake prediction for the key monitoring regions in south-western Yunnan was made by Seismological Bureau of Yunnan Province, from April to June 1997, but there was no expected earthquake occur red during this period. Because of the distinct background of M6 earthquake in south-western Yunnan region and the obvious variations in precursory anomalies in Yunnan, it is thought that the precursory anoma-lies w ere results of strengthened regional stress field. The relation between anomaly and earthquake seems to bean attendant relation between brothers, but not causality between father and son, which is the main cause of false earthquake prediction.

Key words: Prediction practice, Cause of false prediction, Regional stress field, Re-lation between anomaly and earthquake