Fatigue of turbine blade is of importance to the failure of aeroengine. Due to the fact that there are various uncertainties during the manufacture and operation, the randomness of the fatigue damage and life of turbine blade are presented. Based on direct probability integral method (DPIM), in this study, the structural parameters, working condition and vibration environment are considered to be random, and the fatigue life and reliability are evaluated for turbine blade. First, the low-cycle fatigue problem is modelled as stochastic static system with random parameters, and the high-cycle fatigue problem is considered as stochastic dynamic system under random excitations. Then, the DPIM is utilized to deal with the two types of fatigue problems in a unified manner. The probability density functions of accumulated damage and fatigue life of turbine blade for low-cycle and high-cycle fatigue problems are solved, respectively. Finally, numerical examples demonstrate high accuracy and efficiency of the proposed method by comparing with Monte Carlo simulation and other methods. It is indicated that the DPIM is a unified method for predication of random fatigue life for low-cycle and high-cycle fatigue problems.