Abstract: There are two possible methods proposed in RCC-M paragraph ZG to perform the fracture analysis. The first method is easy to carry out. But the calculation result is too conservative and difficult to satisfy the criterion of RCC-M. The second method is to perform the fatigue crack growth analysis. This method is very complex. And there is too much calculation using this method. This paper provide a fatigue crack growth program writing with ANSYS code APDL commands. Calculation of reactor pressure vessel fatigue crack growth is performed using this program.