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In this paper, a new type of magnetic field optical sensor based on Faraday effect created by the magnetization rotation process in each stripe magnetic domain is proposed. For these sensors, (Tb0.19Y0.81)3Fe5O12 ((TbY)IG) crystals were used as Faraday element. At the wavelength of 1.3 μm, the obtained sensitivity is 4.7×10-3 %/A/m. The small linearity error of the sensor output is also obtained in a wide dynamic range between 1 A/m and 104 A/m. When the magnetic field is applied perpendicularly to the easy axis, we consider that a linear magnetization curve without hysterisis is obtained by a rotation of domain magnetization. This assumption is confirmed by experiment. The experimental results such as the sensitivity, the linearity error and the signal-to-noise ratio were explained well by the proposed model.