Abstract: The problem of water-mud bursting for tunnel crossing water rich fracture zone often affects the construction progress and brings potential safety hazards in tunnel engineering.A risk assessment model is established based on the fuzzy comprehensive evaluation method and the analytic hierarchy process.From the perspective of the three major influencing factors of engineering geology，hydrogeology and engineering construction，the weight and membership of each refined influencing factor are determined.The classification of objective factors depends on specifications，and the classification of subjective factors adopts expert judgment.After the results of membership of each factor are collected，the risk level of water-mud bursting for tunnel crossing water rich fracture zone is evaluated according to the final score.Finally，through the analysis of engineering cases，various indicators are comprehensively evaluated and verified.The results show that the risk level of water-mud bursting assessed by this model is in good agreement with the actual situation of the project.The feasibility and applicability of the method are verified，and the risk level obtained is reasonable，which can provide reference for the risk assessment of water-mud bursting geological disasters when the tunnel passes through water rich fracture zones.