天然災害風險高低乃取決於天然災害程度與脆弱度高低之交互影響，南投為一典型的山地縣市，其聚落所承受多為山地型態的風險，所以多以應付山地災害為主，防災關係到人類社會系統對於災害的應變和預防的能力加上經濟產業的考量合成社會經濟脆弱度(Socio-economic Vulnerability)；本研究使用南投縣的人口結構、產業特性及資源分配等資料針對根據脆弱度定義所歸納與修正之具代表性的24項指標變數，以熵權重的計算方式量測南投縣各鄉鎮市的社會經濟脆弱度值數，以評估南投縣各區域的社會經濟脆弱度，結果以仁愛鄉、信義鄉、集集鎮、水里鄉為前兩級的高脆弱度區域，埔里鎮具最低脆弱度，南投市、竹山鎮、草屯鎮為次低脆弱，顯示山地鄉鎮區域的脆弱度多半大於平地的城市區域。

The level of natural disaster risks depends on the interactive relationship of vulnerability and disaster. Nantou county, as a rugged region, tolerates risks from the large area of mountainous terrain. The resistance to natural crisis of the townships is related to social-economic vulnerability. Social-economic vulnerability combines society and economy concepts to discuss the ability of a social system to react and prevent natural disasters. The population structure, industrial characteristics and resource allocation are important parts that affect the social-economic vulnerability of the region. Based on these information, we define 24 vulnerability indices as parameters to evaluate the social-economic vulnerability of each district in Nantou county by use of a entropy weight method. The results showed that, Renai, Xinyi, Jiji and Shuili townships are listed as most social-economic vulnerable, whereas Nantou city, Zhushan and Caotun towns are listed as the second most vulnerable, and Puli town is listed as the lowest vulnerable, the mountainous townships are generally more vulnerable than flat urban areas.