Eight N (substituted pyrimidin 2 yl) N β (or γ )pyridinecarbonyl thioureas are synthesied and tested for biological activity.All of them are new compounds and their structures are comfirmed by IR, 1HNMR and elementary analysis.The preliminary biological test shows that some of the target compounds have excellent inhibitory activities against root and stalk of dicotyledon plant (such as rape) and a good regulating activity for plant growth of monocotyledon(such as corn).