To address the current lack of dedicated dynamic calibration devices for FBG strain sensors in the calibration field, as well as issues such as limited response amplitude and insufficient reference waveform stability in conventional devices, a dynamic calibration device for FBG strain sensors based on the confined whip-tail effect was developed. The device employed a constant-section cantilever beam as the strain standard generator, a packaged piezoelectric ceramic actuator as the high-resolution displacement exciter, and a high-precision laser displacement sensor as the deflection transducer. It utilized a bilateral limit mechanism to perform controlled nonlinear modulation of the cantilever beam’s response. Two-degree-of-freedom and single-degree-of-freedom dynamic models were established for both constrained and unconstrained conditions; based on Euler–Bernoulli beam theory and the device model, a conversion relationship was established between the laser-measured deflection and the surface strain at the sensor attachment position; and an experimental prototype was constructed. Experimental results show that, under conditions of a piezoelectric excitation amplitude of 50 μm and a unilateral limit gap of 30 μm, the device achieves a 95-fold increase in response at 25 Hz compared with the unconstrained response. A significant first-order resonance whip-like amplification effect occurs near 23.23 Hz, with a measured deflection amplitude of 22.611 mm and a peak-to-peak value of 45.221 mm. The device exhibits stable output waveforms within the 1–50 Hz range; the amplitude repeatability error in continuous repeated experiments is 0.02%, and the resolution is better than 0.5 με. It is evident that the developed calibration device can provide a high-amplitude, highly stable reference standard for the dynamic calibration of FBG strain sensors, demonstrating excellent engineering application value.