Because hydraulic amplification can be used to realize good output performance,a kind of flexible braille contact device based on piezoelectric drive was designed.The structure and working principle of the braille contact device were explained,and theoretical analysis and parametric design for the hydraulic amplification unit were presented.The relationship between the displacement amplification ratio and diameter and height of the fluid cavity was obtained by using MATLAB simulation analysis.The output displacement of the piezoelectric vibrator and the flexible film under different driving voltages was measured by using the laser micrometer,the experiment was consistent with the theoretical analysis and the correctness of the theoretical analysis was verified.Finally,the experimental device was tested.The results indicate that the displacement amplification ratio is 4.16 and the contact displacement formed by the flexible film is 0.226 mm when the fluid cavity diameter is 20 mm,the cavity height is 3 mm,the filling water is 0.9 mL and the resonance frequency is 317.5 Hz,which can be perceived by the blind.It prove that it is feasible and effective.