Abstract: the single short-term anomaly of water radon, mercury, water temperature and geomagnetism is extracted by using slope k and interrelated coefficient r. And the synthetic indexes are extracted by means of calculating the data got from different observational points through Group Uneven Method. The results show that in Yunnan area, for the earthquakes with M≥ 5.5, the earthquake precursors have significant characteristics of group mutation. The characteristics are of the ideal short-term effect for the earthquake prediction and its credibility has been proved to reach 97.5% by R-check Method.

Key words: Extraction of short-term precursor, Group uneven calculation, Prediction of earthquakes M≥ 5.5, Yunnan area