Using a laser monitoring observation technique, the solubility of ammonium sulfate in pure water, sulfuric acid solution (pH = 2.5), and ferric sulfate solution from (278.98 to 338.35) K was experimentally measured by a synthetic method. The results were correlated with a semiempirical equation and provided an indication of the solution nonidealities on the solubility of the solute, which can be used as a useful model in the production of ammonium sulfate.