Mountain hazards represented by flow debris and landslide occur frequently in the upper reaches of Minjiang River,which bring serious damage to the region. We take the upper reaches of Minjiang River as the study area and choose eight disaster-causing factors as the discriminant factors,which are slope,aspect,slope shape,relief,distance to rivers,distance to faults,engineering geological petrofabric and vegetation coverage. The natural break is adopted to process the state division. Contribution of each disaster-causing factor to the mountain hazards is analyzed through the information value model. Combining the precipitation data,the risk zoning is made to the upper reaches of Minjiang River. Research shows that,slope lager than 33.96°; relief larger than 220 m;aspect which is east,south east or south; concave slope larger than 27.19 m; distance to rivers less than 0.64km and distance to faults less than 3.19km are the favorable conditions for mountain hazards occurrence. The area of medium,high and very high levels is 7392.5 km~2 which accounts for 29.8% in the whole place. And there is an obvious trend that these hazardous areas lay along the mountain valleys and river valleys. The mountain hazards risk of the upper reaches of Minjiang River decreases from southeast to northwest as a whole. The zoning result is well consistent with the actual mountain hazards situation in study area. Thus,to some extent,it can provide scientific guidance for the selection of urban construction in this area as well as the prevention of mountain hazards.