The invention relates to a production method of potassium sulfate fertilizer granules. The production method comprises the following steps: crushing potassium sulfate and iron oxide red, mixing potassium sulfate and iron oxide red, preparing a binder, and performing granulation. The potassium sulfate granulated fertilizer product produced by the method is uniform in particle size, round and tidy in particles and smooth in surface, and the particle strength reaches the national fertilizer requirement standard. The potassium sulfate fertilizer particles cannot be pulverized in the transportationand application processes, and can be used as a raw material of a compound fertilizer.