Turbine blade is the core component and vulnerable part of the gas turbine. It works in a very poor environment, and bears huge alternating stress under high temperature condition. Therefore, turbine blade is the most frequently failure component in the gas turbine and the main failure mode is fatigue failure due to crack propagation. According to the start working condition of a gas turbine, the load spectrum is worked out. The dangerous location of blade failure is determined by transient thermal elastic-plastic finite element analysis (FEA), and the solid model of cracked blade for FEA is established. According to the J integral strength criterion and the results of transient thermal elastic-plastic FEA, the non-probabilistic reliability of the cracked blade is analyzed, so a new method or way is provided for the reliability analysis of imperfect structures.