The invention discloses a spline interpolation compensation method for explosive separation impact data. The method includes the steps that an interpolation function is constructed, impact measurement data are extracted and preprocessed, the interpolation function is established, a time point needing interpolation is calculated according to an even sampling principle, and an approximating value of an impact signal on the time point is calculated according to the interpolation function acquired through the third step. By the adoption of the method, hardware equipment of a measurement system does not need to be changed, the advantage that measurement cost is not increased is achieved, the interpolation function only needs to be selected according to the measured data, digital interpolation is then conducted, and therefore the two types of errors can be reduced simultaneously. The spline interpolation compensation method can also be used for reference in impact analysis of other types.