To study the dynamic fracture performance about the compact tension(CT)specimen,the split Hopkinson bar was improved,and a kind of clamping device between the loading point of incident bar and transmission bar was designed to study the dynamic fracture test on the CT specimen. In terms of tensile stress wave propagation,the finite element method based on ANSYS/LS-DYNA had been adopted to realize the dynamic fracture response and calculate the relative parameters about the dynamic fracture toughness. The result shows that,the stress distribution in the CT specimens from the asymmetric state to the symmetric distribution needs about 80 μs,and then stress distribution cloud in the specimen becomes symmetric and the stresses on two points become equal. Thus the CT specimens come to the balance state,meeting the dynamic fracture toughness test requirements. The effect of the chuck section and the pin diameter on the stress wave propagation and stress balance was studied,which will provide the basis for the further research on the Hopkinson tensile bar and the dynamic fracture test on the CT specimens.