Abstract: In this paper, a method of numerical integration is presented for data processing of strong motion accelerograms in the correction of distorted amplitude frequency response obtained by the type RDZI-12-66 automatic triggering accelerograph, galvanometrically recorded. The zero base-line correction of an accelerogram is done by means of a high pass digital filter and a computer program is compiled for this purpose. The duration traces of the corrected acceleration, velocity and displacement are respectively plotted. The Fourier spectra of the accelerograms before and after correction are calculated and discussed.The corrected accelerograms can accurately represent the absolute ground acceleration within the frequency band of 0.09 cps and 25 cps of the instrument.