Abstract: In order to improve measuring accuracy of nano coordinate measuring machine probe and meet requirements of accurate measurement for complex surfaces or micro structures, a novel optical fiber Bragg grating (FBG) based micro contact probe system is proposed in this paper. The probe has high sensitivity and repeatability. This new FBG probe has a molten spherical top, and as a strain sensor, FBG is built on the spindle. Basic principle of fiber-optic probe is introduced. The finite element software ANSYS 11 is used to simulate strain distribution of probe in axial and lateral loads. Results show that simulation analysis agrees well with theoretical calculation. Sensitivity and resolution of fiber probe are tested by experiment. Experimental results show that performance of probe is measured by piezoelectric transducer with displacement resolution of 1.5 nm under axial load condition, and measurement resolution of fiber probe is 60 nm. Fiber probe has a high sensitivity and resolution, and its performance can meet requirements of actual measurement.