Abstract: Pipeline transportation is a crucial step for the success or failure of paste filling. To ensure the reliability of pipeline transportation in the paste filling system, based on the Man-Material-Environment-Management (MMEM) theory, five factors including personnel, management, material, pipeline, and environment were selected as comprehensive evaluation indicators, and an evaluation index system for the safety assessment of filling pipeline blockage accidents was constructed. The dimensionality of each evaluation index was unified and converted into cloud model parameters to classify the indicators. The combined weighting method, which integrates the analytic hierarchy process (AHP) and the criteria importance through intercriteria correlation (CRITIC) method, was adopted to determine the comprehensive weights of the evaluation indicators. Based on the extension cloud theory evaluation method and the filling mining safety assessment model, the risk degree of filling pipeline blockage accidents at the 2918 working face of Yuxing Coal Mine was evaluated. The results show that the evaluation results obtained by this method are in good agreement with the on-site verification results, which provides a certain reference value for the risk assessment of filling pipeline blockage accidents.