Abstarct: Reliability analysis is a practical and applied process that is performed during both design and operation steps. The result of this process is the control, evaluation, and assessment of potential failure existing in the system and, ultimately, prediction of failure rate of the studied system. Along with reliability, maintainability is a controlling parameter with regard to the performance of each sector or subsystem. In this regard, an additional element to reliability and maintainability is the system or machine availability through which it is possible to assess the entire condition of the system. In the present dissertation, an attempt was made to investigate the operation of earth pressure balance tunnel boring machine installed in Line 1 of Tabriz Metro. The machine used in this project is manufactured by NFM Company (of France). Studying the overall structure of the machines, six systems including, mechanical of backup part, mechanical of body (front) part, electrical, hydraulic, pneumatic, and water systems were introduced to be studied as subsystems of the machine. Data and information of project delays caused by these systems malfunction over 26 month period of excavation were gathered. As the next step, the failures and repairs data of each subsystem was classified. The applied statistical analyses showed that failure and repairs data of all subsystems follow classic statistical distribution functions. Therefore, by deriving the parameters of failure and repair density distribution of the functions, the reliability, maintainability, and availability of system were determined for each subsystem. In the next step, baxsed on the obtained results and structure of the subsystems, the analysis for the entire system was performed. The obtained results showed that the reliability level of the studied systems will reach 0 after 55 hours of excavation if no action is taken. Also the availability of the machine was calculated as 48.03%. Also, for improving the performance and reducing unpredicted failures of the TBM, a maintenance and repair plan was recommended for the whole tunneling machine in Line 1 of Tabriz Metro. Finally the estimation of mean residual life for the cutting tools of the machine was performed considering operating environment.