For various uncertainty problems in the super long tunnel construction risk evaluation, a new risk evaluation method based on the uncertainty measurement theory is proposed. Fifteen uncertainty measurement function evaluation indexes (e.g. the supporting measures) are chosen according to the characteristics and the causes of the safety accidents in the super long tunnel, and an uncertainty measurement evaluation model based on the uncertainty measurement theory is proposed for predicting the construction risk of the super long tunnel. The weight of each index is calculated by using the information entropy, and the risk grade is predicted in accordance with the confidence identify rules. A new super long railway tunnel is taken as an example, the comprehensive risk rating of the super long tunnel is predicated successfully and its risk level is shown to be the gradeⅡ. The risk evaluation for the super long tunnel construction not only includes the risk grade of the super long tunnel construction period but also reflects the dangerous sources during the super long tunnel construction.