The key to assess dam safety is to qualitatively evaluate each individual indicator. We determine the specific quantitative evaluation values of the dam safety level, and then define the model parameters of the dam safety level by non-linear fitting mathematical analysis tool (Matlab). Thereby, on the basis of Logistic model, we can get a precise quantitative evaluation model, which accurately fits the quantitative evaluation parameters with the determination coefficient of 0.998 6. In this way, the qualitative evaluation of individual indicators is transformed into quantitative evaluation. 