Several new aroyl ureas IIIa~e were synthesized by reaction of 2-amino-5-(3-pyridyl)-1,3,4-thiadiazole with substituted benzoyl isocyanates, in the yield of 69.5%, 67.2%, 73.1%, 66.8% and 71.6% respectively. The structures of the products were confirmed by IR, 1H NMR, MS and elemental analysis. The plant-growth regulating activities were tested on the title compounds. The results of preliminary tests indicated that these compounds exhibit some degree of auxin activity and relatively good cytokinin activity at the concentration of 10 mg/L, where the promoting rates towards cytokinin of N-(4-bromobenzoyl)-N'-[5-(3-pyridyl)-1,3,4-thiadiazol-2-yl]urea (IIIc) and N-[4-(trifluoromethyl)benzoyl]-N'-[5-(3-pyridyl)-1,3,4-thiadiazol-2-yl]urea (IIIe) reach above 40%.