Abstract: Upon treatment of 1-aryl-4-ethoxycarbonyl-5-amino-1,2, 3-triazoles (1) with excess acetic acid, acetic anhydride, acetyl chloride, benzoyl chloride, formamide, etc., fourteen new derivatives of 1 were obtained in good yields, such as, 1-H-4-ethoxycarbonyl-5-arylamino-1, 2, 3-triazoles (2b～d), 1-RCO-4-ethoxycarbonyl-5-arylamino-1, 2, 3-triazoles (3a～d), 1-aryl-4-ethoxycarbonyl-5-acetylamino-1,2,3-triazoles (4a～d)and 1-formoyl-4-ethoxycarbonyl-5 -p -nitrophenylamino- 1, 2, 3-triazole (5a), 1- benzoyl-4- ethoxycarbonyl-5-p -nitrophenylamino- 1,2,3 -triazoles (5b), 1-p-chlorobenzoyl- 4- ethoxycarbonyl -5-p-nitrophenylamino-1,2, 3-triazoles (5c). Some of them were rearrangement products. Structures of all heterocyclic compounds were identified by elemental analyses, IR, ¹HNMR and MS. Inhibiting effects of some compounds on B. substili, E. coli, E. aerogenes and S. aureus were also screened.