Abstract: The unascertained measure theory is applied to the risk assessment of freezing method. Aiming at the uncertain risk factors, the risk assessment model is established according to the unascertained measure theory and the information entropy theory, and the rank of risk hazard is forecasted. According to the actual situation, 19 critical risk factors were selected as the evaluation index, the evaluation index system was established, the single index measure function was established according to the qualitative and quantitative data, the measure of the rating of each index was calculated, the weight of each evaluation index was calculated by the information entropy theory, To avoid the subjectivity and preference of expert judgment. Finally, the comprehensive risk rating of the freezing method is calculated based on the multi-index comprehensive measure of the evaluation vector and the confidence criterion. This model is applied to the Wanfu coal mine in Shandong province. The practical application results show that the predicted results are scientific and reasonable and consistent with the actual situation in the field, which shows that the method is feasible and has strong adaptability for the coal mine freezing method. New ideas, at the same time for other similar projects to provide reference.