Abstract: <SPAN lang=EN-US>Synthesis process of potassium sulfate by gypsum double salt method was studied and improved.In allusion to the first reaction of the process,effects of influencing factors,such as reaction temperature,reaction time,mixing intensity,watering quantity,and ratio of mixture etc.on the whole process,were investigated to seek for suitable reaction conditions and the methods for recycling by-product calcium carbonate were discussed.As for the second double decomposition reaction,methyl alcohol was confirmed as the additive solvent through research and analysis,which increased the yield of potassium oxide to 90% above.In addition,methyl alcohol could be recycled and ammonium chloride could be by-produced.Influence of the factors,such as temperature of reaction on the yield of potassium oxide,was also investigated.The process condition of reaction was determined by means of orthogonal experiment.The total industrial process had no waste residue discharge and the process was simple and clean.Natural gypsum and ammonium hydrogen carbonate could be changed into higher value-added potassium sulfate and ammonium chloride through this new effective clean production process.<BR></SPAN>