The dispersion effect in the Hopkinson pressure bar high-g loading technique was caused by the lateral inertia motion of the particle, leading to an inaccurate acceleration in peak and duration. Based on the Fast Fourier Transform (FFT) approach, the dispersion effect was corrected. Then, acceleration pulses at different locations along the pressure bar were compared to check the dispersion effect. In addition, before and after dispersion correction, the acceleration pulses on the specimen were obtained under different pulse loading, and the errors of the peak and duration were analyzed. Results show that the acceleration pulses at different locations of the bar are different in peak and duration due to the dispersion effect, and the errors of the peak acceleration on the initiator are more than 10%. The errors of the acceleration duration depend on the pulse shape, but the absolute errors are all less than 6μs. As for the dispersive pulse, dispersion correction is a necessary procedure to obtain a more accurate acceleration pulse.