Abstract: The relationship between pre-shock drought and strong seismic activity has extensively drawn people's attention. From the relationship between the precipitation and the study ot strong seismic activity (Ms6) in the Keping - Wuqia region,we have found that 85.7% of total events occurred under the drought background of one to two years prior to the shocks and the magnitude varied with the size of drought region. In this paper we also discuss the characteristics of precipitation anomaly before the great Wuqia earthquake (M7.4) of 1985,esiimating the efficiency of precipitation factor in earthquake prediction by using the .R-value method of appraising precursory information with good effect.The result shows there is a certain inherent relation between the drought in a large area one to three years prior to the event and the magnitude of strong earthquake. This relationship between drought and earthquake can be considered as one of the bases in medium-term synthetic prediction of strong earthquakes.