One of the key factors in accurately deriving the stress-strain relationship of materials through scientific data processing methods is the SHPB (Split Hopkinson Pressure Bar) experiment. In order to relatively accurately obtain the Johnson-Cook constitutive relationship of 2A12 aluminum alloy material, an SHPB experiment was conducted on this material. Based on the analysis of the wave characteristics of the transparent reflected wave, the MAD-wavelet transform composite filtering method was developed and the wave method was improved. A method based on the Johnson-Cook model to analyze and determine the yield stress and yield strain was proposed. Research shows that the normalized engineering stress-strain curves obtained using these improved methods have good overlap, and the yield stress data provided has good regularity. Regarding the influence of the problem that the phenomenological yield strain obtained from the experiment is much greater than the actual yield strain, the calculation methods of the true stress and true strain were improved, and the Johnson-Cook constitutive equation of the 2A12 aluminum alloy material was given. The results show that the strength strain rate strengthening factor of the 2A12 aluminum alloy material is 0.267, the reference dynamic strength is 374 MPa, the plastic strain strengthening coefficient is 397 MPa, and the strengthening index is 0.47.