Abstract: The dynamic finite element software ANSYS/LS-DYNA was used to simulate the SHPB dynamic tests during various projectile velocities on rock specimens with a single fissure.Those undetermined coefficients in the mathematical expressions of rock strength criteria was gained by the regression analysis of simulation data while the relation between average strain rate and undetermined coefficients was studied as well.The results show：Several commonly used strength criteria in rock mechanics，including Mohr-Coulumb criterion，Hoek-Brown criterion，Griffith criterion，are not suitable for the rock specimens with a single fissure while Fairhurst criterion is the only one which fits well for the condition in the paper.With the average strain rate increase，two undetermined coefficient among Fairhurst criterion raised according to the linear relation.Based on this，the dynamic Fairhurst criterion for rocks with a single fissure is built.At last，the fitting analysis of the dynamic rock strength criteria through the computer simulation of dynamic splitting tensile tests has provided a new thought for more conveniently and efficiently grasping the rock failure criterion.

Key words: ANSYS/LS-DYNA, Single fissure, Rock, SHPB, Dynamic strength criteria