The invention discloses a method for determining the tensile elasticity modulus of a fragile material in an SHPB (split Hopkinson pressure bar) split tension test, which comprises the following steps: placing a cylindrical sample on an SHPB split tension test machine; exerting an impact load on the sample along the radial direction of the sample; measuring the displacement of the sample in a stress-loading process; and calculating the dynamic tensile elasticity modulus Edt of the material by utilizing the formula disclosed in the specification, wherein P(t)max is the maximum value of the dynamic load, L is the length of the sample, D is the diameter of the sample, mu is the Poisson ratio of the sample material, and Delta ut is the damage displacement of the central diameter length of the sample along the vertical loading direction when the sample is damaged. The method for determining the tensile elasticity modulus of a fragile material in an SHPB split tension test can be easily implemented and can acquire accurate measurement result.