Abstract: In order to study the stress -strain curve, dynamic uniaxial compression strength, dynamic elastic modulus, peak strain and variation law with the strain rate increased of the limestone with different length-diameter ratios, a Split Hopkinson Pressure Bar (SHPB) test device was applied to the impact loading test under seven different strain rate grades on the two group limestone samples with different length-diameter ratios.The results showed that with the strain rate increased, the stress -strain curve would have different variation law after the peak reached and would have obvious rate dependence. The dynamic uniaxial compressive strength of the two group samples would have a power increased with the strain rate increased. The strength of the sample with a length diameter ratio of 1.0 would have a strong sensitivity of the strain rate than the sample with a length diameter ratio of 0.5 and would have a obvious size effect. The dynamic elastic modulus and the peak strain would be increased with the strain rate increased. Under the same strain rate, the dynamic elastic modulus of the sample with a length diameter ratio of 1.0 would be higher than the sample with a length diameter ratio of 0.5. Under the same strain rate of the dynamic compression failure state of the sample, the failure degree of the sample with a length diameter ratio of 0.5 would be higher than the sample with a length diameter ratio of 1.0. When the strain rate was low, the sample would have a axial split failure. When the strain rate was high, the sample would have a partical fine failure.