The high measurement accuracy in dynamic tension testing is required for designs and numerical simulations based on the accurate modeling of stress-strain relations at various strain-rates. The non-coaxial Hopkinson bar method (NCHBM) is one of the recently proposed methods for dynamic tension tests. In this study, the accuracy of the stress-strain relations obtained on the basis of NCHBM was investigated by the analysis based on FEM and by experiment. The FE models of NCHBM apparatus and plate-type specimens of various dimensions were made in detail. The target materials employed in this study were mild steel and SUS316 stainless steel. The effects of the rising, the dimensions of specimen, and the strain rate were examined systematically. The results calculated for the specimens of SUS316 were compared with those obtained by experiment. At last, the improving methods of the specimen fixation were proposed.