Abstract: Aimed at the characteristics of the geological hazard in Guizhou province, the continuous rainy days, continuous non-rainy days and the early accumulative rainfall are chosen to calculate the rainfall principal component with the method of Principal component analysis. Then the risk prediction model of geological disaster is built by the generalized additive models(GAM) under the topography in Guizhou province respectively with the 10-day cumulative rainfall, the 10-day effective rainfall and the rainfall principal component. The results after being inspected show: (1) The rainfall principal component explains objectively the effect of the precipitation on the geological hazards risk. The geological hazards happened mostly in both cases of the early continuous precipitation and the sudden rain after the early continuous non-rain. (2)Under the same underlying surface, the method of the rainfall principal component is better than the other two about the forecast verification result, and the refinement of geologic hazard is more close to the actual situation. (3)The choice of different rainfall factors affects the importance of geological hazard differently. The precipitation makes the most prominent contribution to the risk of geological hazard with the method of rainfall principal component. and the rest factors to the geological hazard follow the order of curvature, altitude, aspect ,slope and profile curvature.