Abstract: Graphite has high scattering and low absorption cross section of neutron. Therefore, it is widely used in high temperature gas-cooled reactor (HTR). Because of the variability of strength, the probabilistic method is more appropriate to evaluate the failure of graphite than deterministic method. The failure probability model via subroutines of ABAQUS was developed and the applicability of Hindley model on fine-grained graphite was studied in this paper. A modified model was proposed and verified with test data. The result shows that Hindley model is too conservative and modified model fits data better. This model is more appropriate and can be an important reference to the application of domestic graphite in nuclear power plant.