A micro displacement magnifying mechanism for the piezoelectric brake is presentedin this paper. Taking the laminated piezoelectric ceramic as drivers of amplifier,the displacement of piezoelectric multilayer actuator is amplified with the flexure hinge amplifier based on the principles of triangle amplification.The motion and amplification mechanism of the amplifying mechanism are analyzed, and the mechanical model of the braking system is established.The finite element model of the mechanism is simulated by ANSYS software, and the output characteristic is tested on the prototype.The experimental results show thatthe mechanism can amplify the output displacement of the laminated piezoelectric ceramic to 3.2 times, which is close to 4 timesby the finite element simulation. The first order natural frequency is 1 814 Hz, the maximum output force is 44.1 N(under 150 V voltage), and the mechanismhas good linearity, high resolution,small hysteresis effect.