Abstract: Because there are lots of uncertain factors to influence a project,experts usually have to use some fuzzy words when they evaluate risks of a project.To evaluate quantitatively uncertainties of a project,this paper presents a new method of analyzing project risks.First,we can quantify these fuzzy words by using the fuzzy set theory,that is to say,we can express the project risks by using a kind of simple fuzzy number\_\_triangular fuzzy number;then we can judge the degree of the project risks by comparing the triangular fuzzy numbers,and the dominant project can be selected by comparing the risks of various projects.Finally,we also consider that how to quantify accurately uncertainties of a project is a very attractive problem,and we will make further researches on it.