Aiming at the problem that the randomness and complexity of inverted siphons cannot be comprehensively reflected by safety evaluation at the present stage, and the membership function of evaluation index based on analytical formula tends to be conservative, AHP method was used to construct the analytic hierarchy process system including multi-dimensional factors, in which the membership function of evaluation index was constructed by using cloud model theory. A comprehensive evaluation method based on AHP-cloud model with on-site monitoring and detection information fusion was then proposed, which was applied to the safety evaluation of an inverted siphon at the Huangshui River branch in the Middle Route of the South-to-North Water Transfer Project. The results show that the inverted siphon safety evaluation method based on AHP-cloud model is reasonable and feasible. The evaluation results can reflect the comprehensive safety state of the inverted siphon during operation, which can provide reference for its safety management.