In consequence of climate change, a country is faced with a series of economic, social and environmental problems. Which has affected the social and government stability in a country. First, in order to evaluate a country's fragility, we established a set of metrics including political economy, resources and society. Using space vector synthesis, we could calculate the score of vulnerability index. According to the principle of Natural fracture classification, finding that (0,0.37], (0.37,0.69], (0.69,1) is divided to stable, fragile and extreme state. Next, we selected Somalia, analyzing its' climate characters: On the one hand, droughts lead to water resources reducing, on the other hand, floods lead to city submerging. Assumption that two situations, including "adequate water resources" and "well-organized government ",compared with the present situation ,we concluded that these effect contributes to less vulnerability. Finally, we studied the adaptability of the model. In terms of a city, our model only needs to be adjusted in certain aspects. For a continent, we use the weighted average of the proportions of the countries in the continents and their vulnerabilities as the state's vulnerability index to improve our model.