Abstract: On the basis of ABAQUS explicit solution, split-Hopkinson tension bar(SHTB) model is built up to investigate the mechanical properties of coal and rock under dynamic tensile impact loading. Thus, the constitutive model of Z-W-T is selected and improved to research the stress-strain relation under high strain rate. The results show that the SHTB system established in this numerical simulation is able to realize a steady strain-rate loading. Besides, the improved constitutive model describes its mechanical behavior well. The strain-rate effect and strain hardening effect is obvious in coal's dynamic tension.