Abstract: Sulfonylurea herbicides,widely applied in agricultural crop protection worldwide,were a milestone of the herbicide development because of its ultra-high activity at low application rates with low toxicity and environmentally benign characteristics.In order to study further structure activity relationship of these kind of herbicides,on the basis of our former studies,16 novel 4-phenylpyrimidine sulfonylurea compounds were rationally designed and synthesized using monosulfuron and monosulfuron-ester as leads.All structures of the new compounds synthesized were confirmed by 1H NMR,MS and elemental analysis.Preliminary herbicide screening indicated that,most compounds show certain extent inhibitory activity to various weeds at 1.5 kg/hm2,the inhibitory activity to dicotyledonous weeds were better than those to monocotyledonous weeds.Phenyl substituted pyrimidines were not benefit to improvement of herbicide activity.