In order to control the decomposition of metalworking fluids under the premise of reducing or even not using chemical fungicides,a new biological antibacterial technology was proposed.Firstly,a kind of pseudomonas aeruginosa （Y1）was extracted from the metal working fluid in service,and the growing characteristics of the dominant microorganism Y1 were studied,and then the antibacterial effect of Y1 under different experimental conditions was analyzed.The results show that the optimum temperature for Y1 growing is 40 ℃ and the optimal pH value is 60.The microorganism Y1 has good tolerance to BK,WSplus and other chemical fungicides.In the mixed bacteria cocultivation test,the forced spoilage test and the actual application field simulation test,the mciroorganism Y1 shows good antibacterial effects,which can better inhibit the growth of the main spoilage bacteria F1,F2 and F3 in 1000Ti.The antibacterial effect of Y1 can be better if it worked with a small amount of chemical fungicide.At the same time,the addition of Y1 do not adversely affect the pH value,rust resistance and lubrication properties of the metal working fluid.The research results can provide a new design idea for the development of environmentfriendly metal processing products.