Abstract: Based on the analytical method of the dynamic pattern that proposed in “The Ninth Five-year Plan Project", the spatial and the temporal variation characteristics of Radon precursor before two Datong strong earthquakes have been analyzed. The process to form this method has been introduced. The results show that the characteristic region where variation ratio of Radon in the water in the seismic and adjacent region is obvious and large than 0.06 is existed. The relation in the temporal characteristics between the anomaly region and the earthquakes is expressed as Extension-rapid extension earthquake occurrence continuous extension earthquake occurrence con traction”. It is also associated with medium-term, medium and short term and impending short term anomaly development. The variation of the spatial distri-bution of the anomaly region is closely related to the epicenter, geological structure and geothermal activity. It is suggested that the dynamic pattern method could completely and di-rectly show the anomaly characteristic in Radon precursor and be a new method of Radon anal-ysis for the earthquake prediction.

Key words: Radon in water, Dynamic pattern, Spatial and temporal development characteristics, Datong earthquake