Abstarct: Instability and collapse in underground spaces have always been considered as one of the most important and critical operational risks, which, if they occur, will impose very negative consequences on projects. Due to the importance of instability of underground spaces, sufficient cognition of the factors and parameters affecting the occurrence of instability and predicting this phenomenon in the phases of studies and design, consolidation and even after the construction of the tunnel, will be necessary. Numerous parameters are influential in the discussion of tunnel stability; However, a comprehensive study to evaluate and identify all these parameters has not been provided. Therefore, in this study, identifying the parameters and factors affecting the occurrence of tunnel instability, classifying these factors and ranking their relative importance were considered as the main objectives. To achieve these goals, a multi-criteria decision-making method baxsed on a survey of experts was used. For this purpose, first, by reviewing previous studies, the most important factors affecting tunnel instability were identified and categorized. Then, in order to evaluate and initial weight the factors, AHP hierarchical analysis process was used and the factors were modified and categorized again. After the initial analysis, these factors include 38 parameters and in the form of 6 main indicators, including geomechanical factors, studies and design, support system, consolidation and Ground control, geological and geographical conditions of the site, general, executive and contractual factors and singularities were categorized. In order to evaluate and finalize the factors, the integration of ANP network analysis methods and DEMATEL decision evaluation laboratory and test was used. The relative weights of the components were determined by establishing the network analysis process. Finally, to validate the results, a relatively comprehensive study of the results of actual instabilities and collapses in the projects was performed and the results were compared. The results of this study show that among the main indicators, geomechanical factors, level of studies and design are the most important and general, executive and contractual factors are the least important in the discussion of tunnel instability. Among the parameters, geological features in the group of geological and geographical conditions of the site, correct choice of execution method and consolidations in the group of studies and design, severely fragmented and fault zones in the group of singularities and rock mass quality in the group of geomechanical factors; They had weights of 38%, 33%, 29% and 28% more than other parameters, respectively. A comparison between the results of the ANP-DEMATEL rating method and the statistical study of real instability in tunnels shows that the proposed approach has been relatively reasonable and effective; Which can be used as an effective tool or frxamework to deal with many issues and problems of instability in various fields of tunneling.