A new process for producing potassium sulfate by conversion method of ammonium chloride purified by inducing ammonia was introduced.Refined potassium sulfate mother liquor Ⅱ and crude ammonium chloride mother liquor Ⅳ were mixed and heated. The mixture was reacted with potassium chloride and thermal precipitation potassium ammonium sulfate to produce crude potassium sulfate，and then reacted with potassium chloride to obtain potassium sulfate containing K2O of 51.27%（mass fraction）.After separating crude potassium sulfate，mother liquor Ⅰ reacted with ammonium sulfate and potassium ammonium sulfate through ammonia salting out under the high temperature condition.The mother liquor of thermal precipita tion of potassium ammonium sulfate was separated from the mother liquor.After evaporating a certain amount of water，it was cooled to produce crude ammonium chloride.After dissolving the crude ammonium chloride by the ammonia depleted mother liquor，the mother liquor from salting out potassium ammonium sulfate by inducing ammonia was subjected to steaming ammonia，and then the ammonium chloride containing NH4+ of 33.35%，Cl- of 64.01% and K2O of 0.5% was cooled and precipitated.The recovery rate of potassium oxide can reach 96.5%~97.5% in the closed circuit cycle of the whole process.