For the single crystal (SC) Ni-based superalloys, it is difficult to avoid orientation variation along airfoil stacking line of the SC turbine blade. At the mean time, the loading of turbine blade is uncertainly during the working. In this work, the creep life of the SC turbine blade is determined by the finite element analysis (FEA) based on the crystal slip theory. The orientation variations are measured based larger numbers commercial turbine blade made of SC superalloys. Furthermore, Monte-Carlo method and the forth moment method are presented to analysis the reliability for creep life of SC turbine blade under random crystal orientations and random loads based on the FEA method. The basic variables sensitivity are comprehensively analyzed by the forth moment method.