The prismatical PbSO4 microcrystals were successfully synthesized by precipitating Pb2+ ions with SO4 2− ions, which were generated from the reduction of K2S2O8 in the presence of EDTA under N2 atmosphere by γ-irradiation. It was found that EDTA and the controlled release of SO4 2− play important roles in the formation of the microcrystals.