Effects of abamectin,applied at 1,5,10,50 or 100 mg kg^-1,on vegatable-growing soil microorganisms and their respiration,and the activity of urease,dehydrogenase and catalase,in vegetable fields were investigated.Results show that when it was low in application rate (1～10 mg kg^-1) abamectin,stimulated slightly activity of urease and dehydrogenase,but did not have much on soil respiration.And when it was high (50～100 mg kg^-1),it displayed strong inhibitive effects on respiration,and activity of urease and dehydrogenase.Regardless of application rate (1～100 mg kg^-1),abamectin reduced biomass of soil microbes to a varying extent and strongly stimulated activity of soil catalase.