Synthesis method of p-toluenesulfonylurea

The invention relates to a synthesis method of p-toluenesulfonylurea. The synthesis method comprises the following steps: dissolving p-toluenesulfonamide and sodium cyanate in a mixed solution of water and ethanol to react, filtering after the reaction is finished, acidifying the filtered mother solution, and filtering again, thereby finally obtaining p-toluenesulfonylurea. According to the method, no by-product or ammonia gas is generated, the yield of the target product reaches 90% or above, the purity is larger than 99%, the process is simple, operation steps are simple and convenient, theoperation environment is non-toxic and free of pollution, no waste gas is generated, production energy consumption is low, the yield is high, and the method has very high popularization value.