To realize the high-precision tempera ture detection,a new type of fiber optic temperature sensor is proposed based on femtosecond laser micromachining.The femtosecond laser with wavelength of 780nm is employed to ablate a groove-shaped microstructure into the cladding of single mode fiber with Bragg grating (FBG).By magnetron sputtering process,a sensitive film (TbDyFe) is depos ited on the microstructure to make a new fiber optic temperature sensor probe.To the coated annular microstru cture,the mechanism of enhancing sensitivity to temperature is analyzed.The effects of differe nt microstructures on temperature sensitivity are discussed.The experimental results show that the groove-shaped microstructure without coating has almost the same sensitivity with the normal FBG,and it also couldn′t change th e trends of the center wavelength with the temperature.However,as the sensitive film is deposited on the FBG cladd ing with groove-shaped microstructure,its sensitivity can be improved significantly.Moreover,the annula r microstructure has better sensitization effect than the screw thread microstructure,and the temperature se nsitivity can reach 21.37pm/℃.