Abstract: According to the radioactive decay law, a universal formula for the calculation of the fission product activity was deduced. By employing PowerBuilder 10.0, the databases of individual yields, decay paths and decay messages of the fission products were established, and a universal program for the calculation of fission product activity was developed. The nuclear numbers of eight fission gas products were calculated. The results are in good agreement with the reference results. The program provides a convenient tool for the pre-estimation of the fission product analysis.