Based on the railway embankment health monitoring, this study developed an embankment small deformation monitoring system based on FDM (Fused Deposition Modeling) and FBG (Fiber Bragg Grating) technology. Using FDM technology and FBG sensing technology to design the FBG sensor monitoring model with package and anchor plate, the relationship between load and soil displacement can be obtained by calibration test. The results show that the displacement has a good linear relationship with the load, and the correlation coefficient reaches 0.99. The test measured a maximum displacement of 0.25 mm, a minimum displacement of 0.05 mm, a sensor sensitivity of 4 nm/mm, and a minimum resolution of 0.62 μm. The feasibility of the sensor is tested by two test conditions, including monitoring the displacement of the embankment under static and dynamic loads. The monitoring data under static load shows that the wavelength and displacement increase stepwise with time, and the minimum displacement of the embankment is successfully collected, which reaches 0.004 mm. The dynamic load monitoring test results show that the sensor can quickly reflect the vertical pressure generated by the vehicle model load.