Abstract: The method to calculate the start point of transmitted wave and reflected wave relative to incident wave is acquired, based on the assumption of one-dimensional stress used in SHPB experiment. This method not only makes the result of SHPB experiment more accurate, but also standardizes the data processing of SHPB experiment; In addition, to calculating the level of classical incident stress wave, another method based on the principle of conservation of momentum is obtained, which can eliminate the influence of dispersion oscillation on determination of level of classical incident stress wave, and then improve the accuracy of calibrating sensitivity of strain gauge during SHPB experiment. So, this method also standardizes the data processing of SHPB experiment. By both of theoretical calculation and numerical simulation, the accuracy of two methods of data processing is validated.