The analysis indicates that the problems existing in several conventional magneto-optical current transducers are related to their magneto-optical media.Therefore

the characteristics of the new magneto-optical medium

magnetic fluid

are investigated in this paper.The results indicate that the magnetic fluid has an obvious linear working space under DC magnetic field

but under the power frequency（50 Hz） magnetic field

its response is the output signal with two times of the power frequency（100 Hz） instead of the power frequency output signal.Compared to the massive glass magneto-optical medium

the Faraday magneto-optical properties of the magnetic fluid are quite different.It is inferred that the strange magneto-optical characteristics of the magnetic fluid under magnetic field are closely related to the formation of the linear chain.