We have developed speedy and effective procedure for the synthesised of 3-methyl-4-arylmethylene-isoxazol-5(4H)-ones compounds using sodium oxalate as a catalyst with ethanol as a solvent. The multicomponent one-pot reaction of substituted aldehydes, hydroxylamine hydrochloride and ethyl acetoacetate at room temperature with new catalyst sodium oxalate in alcoholic solvent added in R B flask with stirring prepared 3-methyl-4-arylmethylene-isoxazol-5(4H)-ones with excellent yield. They have been synthesised and characterized by spectroscopic techniques like FT-IR, 1HNMR and LC-MS mass spectra. In this novel methodology, remarkable advantage is less time eco-friendly catalyst using method compare with other few organic solvent used. Additionally, all synthesised compounds were screened for their anti-bacterial and anti-fungal activities.