Abstarct: Nowadays, technology advancement and the increasing population and on the other hand their needs for more services have caused the demand for public spaces. One of these underground spaces including tunnels which is used in various industries and sciences such as mining, roads and railways, dams, water transmission, urban sewages, metros, military and defense cases, petroleum storage and other uses. To run any of these tunnels, there may be some unexpected events such as: hazards, financial losses and human injuries, and each may likely to be occurred and can affects tunneling project, which is called and referred as Tunneling risks. Today, Risk management systems are an effective tool for serving different departments, organizations, managers and officials. The Western Alborz tunnel on the Tehran-North Highway is one of the major road plans of the country, that according to schedule supposed to be implemented by the use of TBM and mechanized tunneling in a hard rock environment. In this thesis, 17 possible risks were estimated and evaluated by the help of multi criteria decision making methods by analyzing geological characteristics, geometric factors, investment, technical-environmental and political cases. To rank the hazards of mechanized tunneling in the Western Alborz tunnel, by TOPSIS , ELECTRE methods, both of methods have discussed ; fuzzy environment and classical case, also in order to achieve a united result, ranking strategys has been used. According to the mentioned methods, the results of the analyzes show that the experience of tunneling contractors for large diameter tunnels, toxic gas emissions and providing of TBM and related equipments, among 17 most likely risks, are the most important hazards in the Western Alborz tunnel with high risk respectively.