An arched sensitized microfiber magnetic field sensor with temperature compensation based on TbDyFe is proposed. The magnetic field sensor is consisted of FBG, an arched microfiber, and a TbDyFe. Microfiber is bonded to the TbDyFe by UV glue. Compared with the non-arched microfiber, the arched microfiber can convert the elongation of TbDyFe into the change of curvature radius of microfiber, resulting in the shift of interference wavelength, thereby realizing the improvement of the sensitivity. The interference wavelength of microfiber shows a blue shift with the increase of magnetic field intensity. The magnetic field sensitivity is 47. 81 pm/ mT and FBG is not sensitive to the magnetic field. The magnetic field sensitivity of arched microfiber is 11. 66 times higher than that of the non-arched microfiber. During the heating process, the interference wavelength of arched microfiber is blue-shifted and the temperature sensitivity is 43. 02 pm/ ℃ . The interference wavelength of FBG is red shifted and the temperature sensitivity is 9. 34 pm/ ℃ . The magnetic field sensor shows good repeatability and linearity with the increase of the magnetic field. The cascaded FBG is not sensitive to the magnetic field and can realize temperature compensation for the sensor.