Abstract: Dynamic direct tensile tests and Brazilian tests of granite were carried out by use of the loading system developed by the authors,with the axial strain rate ranging from 10-5 to 10-1 s-1.Dynamic strength and deformation properties were studied systematically.It was indicated that the tensile strength of rock material increased with the increasing strain rate.The Young’s modulus of the rock also increased with the increasing strain rate,but the increasing rate was less than that of tensile strength.And it was the same for the critical tensile strain.However,the Poisson’s ratio was discrete.In addition,the mechanism of the strain rate effect of the rock material was primarily analyzed.