Abstract: As an important agricultural and industrial province with a large population in northwest China,Shaanxi Province suffers a lot from the flood disasters,and the damage caused by flood disaster is just second to drought.Therefore,it is necessary and urgent to study the risk assessment and regionalization of flood disaster,whose results have important practical significance to the integrated local flood management.Based on AHP,weighted comprehensive evaluation method and GIS technology,this paper selected 17 evaluation indicators from the subsystem about the fatalness of disaster-inducing factors,the subsystem about the vulnerability of hazard inducing environment, the subsystem about the exposure of hazard-affected body and the disaster prevention and mitigation capabilities to establish flood disaster risk evaluation index system and evaluated the flood disaster risk and regionalize it across the province using social-economic statistics for 2015 and the annual and monthlyprecipitation data from 34 meteorological stations spanning from 1954 to 2015.The results indicated that the level of fatalness of disaster-inducing factors for flood disaster in Shaanxi Province has shown an increasing tendency from north to south which means southern Shaanxi is the region of the highest risk and the western part of Guanzhong Basin, the higher.The risk levels in other regions are relatively low. The distribution of vulnerability of hazard inducing environment varied a lot in space.The highest and higher vulnerable areas include the counties along the Great Wall in the northern Yulin,the Yan'an City,major counties along Weihe River in Guanzhong Basin,the Hanzhong Basin in southern Shaanxi and Ankang urban area. The distribution of the exposure of the hazard-affected body also varied in space.Most of the urban areas and the developed agricultural regions appear of higher exposure.The study also showed that the cities and the developed regions have stronger capabilities in the disaster prevention and mitigation but other regions are relatively weak.In general,the counties of medium to high overall risk account for 61.54% of all the counties in Shaanxi Province,which include Hanjiang Valley,the Danjiang River Basin,the western Guanzhong Basin and Weinan City and they should be the key areas in flood disaster prevention in Shaanxi Province.The results of regionalization are in accordance with the flood history records in Shaanxi Province and the study provided some reference to the relevant government departments,insurance industry and agricultural production.

Key words: county scale, flood disaster, risk assessment, regionalization, Shaanxi Province