The pilot production line of magnetic fluid completed in this project can produce 2000 l magnetic fluid products at full load. The average market price is about 2000 yuan / L, and the ex factory cost is about 605.9 yuan / L. under the condition of full load production, it can create an annual output value of 4 million yuan and a profit and tax of 520000 yuan. It is mainly used in small high-grade loudspeaker for automobile. With the continuous development of automobile industry, the quality requirements for vehicle mounted loudspeaker are more and more stringent. It requires long service life of loudspeaker and good sound lubrication effect, so as to achieve sound simulation effect and superior audio-visual effect.