Abstract Derivatives of phenylurea are one kind of important intermediates,from which the compounds such as pesticide and naphthol AS can be synthesized.o-Chlorophenylurea(��) was synthesized by the reaction of o-chloroaniline with sodium cyanate in acetic acid.The influences of synthesis methods and molar ratio of raw materials on the yield of the product were analyzed through experimental test.And the optimal synthesis method and conditions were obtained,the yield was 96.7%.o-Methylphenylurea(��),m-methylphenylurea(��),p-methylphenylurea(��) and 3,5-dimethylphenylurea(��) were obtained with the same method,the yields were 86.0%,75.0%,85.0% and 84.5% respectively.The structures were determined by IR,MS.