Fifteen new N-5-(1H-1,2,4-triazolyl)-N'-arylformyl ureas have been synthesized by the reaction of 5-amino-1H-1,2,4-triazol-3-carboxylic acid with arylacyl isocyanate. Their structures were determined by ~1H NMR, IR spectra and elemental analysis. The biological activity tests show that some target compounds have a good activity as plant growth regulator, and N-5-(3-carboxy-1H-1,2,4-triazolyl)-N'-o- chlorophenylfonnyl urea, N-5-(3-carboxy-1H-1,2,4-triazolyl)-N'-o- bromophenylformyl urea, N-5-(3-carboxy-1H-1,2,4-triazolyl)-N'-p-(or m-) methyl-phenyl formyl urea have excellent activity of auxin.

Key words: UREA;PYRRODIAZOLE P;BIOLOGICAL ACTIVITY;AUXIN;ISOCYANIC ESTERS P, 1HNMR;;ELEMENTAL ANALYSIS;PLANT GROWTH REGULATORS