Using ammonium sulfate, a by-product of electrosynthesis of p-aminophenol, as raw material, in a self-made box-type electrochemical reactor, titanium-based platinum-plated electrode is used as the anode, lead-antimony alloy electrode is used as the cathode, and Nafion 427 cation exchange membrane is used as the diaphragm to prepare ammonium persulfate. Taking current efficiency and yield as the optimization goals, the influence of various factors on the electrolysis reaction was investigated. The optimized conditions were as follows: the content of p-aminophenol in the by-product ammonium sulfate was less than 0.05%, the initial concentration was 36.5%, the anode additive was 0.06% ammonium polyphosphate, the electrolysis temperature was 15 °C, the current density was 10 000 A*m-2, and the electricity was 72.48 A*h. Under these optimal conditions, 5 batches of repeated electrolysis experiments were carried out, and the current efficiency was higher than 80% and the yield was higher than 55%