Abstract: Heterocyclic compounds had various biological activities,in order to explore novel elicitors with a broad spectrum and highly systemic acquired resistance,a series of 4-methyl-1,2,3-thiadiazole-5-carboxylates were synthesized by using 4-methyl-1,2,3-thiadiazole-5-carbonyl chloride and substituted hydroxyl aromatic compounds as reactants.These reactions were conducted in dichloromethane at room temperature and using triethylamine as acid binding agent.All synthesized compounds including 9 new structures were confirmed by 1H NMR,IR and HRMS.Crystal structure of 2g was cultured and characterized by X-ray crystal diffraction method to validate the detailed chemical structure for this kind of compounds.Bioassay indicated that some compounds possessed obvious fungicidal activity at a concentration of 50 μ g/mL.Among these compounds, 2c,2n and 2o possessed a broad spectrum of fungicidal activity and EC50 value of these compounds ranged from 3.46 to 23.30 μ g/mL.Antivirus activity screening indicated that some compounds possessed good anti-TMV activity and most compounds displayed good inactivation activity against TMV.Moreover,compounds including 2a,2c,2d,2e,2f,2g,2l and 2o exhibited good systemic acquired resistance for tobacco against TMV as compared with positive control agents.