Abstract: A method of processing zero drift data was proposed to solve the problem of zero drift existing in the measured penetration overload data. Based on the method of empirical mode decomposition to extract the signal trend term, the zero drift trend after penetration was employed as the trend during penetration. At last, segmentation correction process was completed using the least squares fitting. After using the methods introduced above to remove the zero drift of overload data, the maximal error between the single integral velocity and the measured velocity is 4.88% when overload happens to the projectile. The maximal error between the double integration displacement and the measured distance is 9.41%. The study shows that the EMD and least-square method can accurately and effectively eliminate the zero drift of overload data and provide useful information for the detonating-control technique of calculating penetration distance.