A three-dimensional (3D) fiber probe is proposed for the measurement of micro parts. The probe is made of a fiber Bragg grating (FBG) that acts as a micro focal-length cylindrical lens (MFLC-lens) of two mutually orthogonal micro focal-length collimation (MFL-collimation) optical paths. The radial displacement of the probe tip is transformed into the shift of the fringe image collimated by the MFL-collimation optical path; the axial displacement of the probe tip is transformed into the power ratio variation caused by the Bragg wavelength shift. Advantages of the probe are high precision, low cost, high measurable aspect ratio, and capability of decoupling the 3D tactility.