The displacement output ability of piezoelectric actuator is limited, for this reason, it was commonly to carry out amplification on its amount of displacement with the aid of flexible mechanism. At here an analysis was carried out on the performance of the commonly used flexible amplification mechanism. A kind of flexible eight-link amplification mechanism has been put forward, and the finite element analysis and theoretical calculation were conducted upon it. A two staged series mechanism has been put forward so as to raise the rate of amplification. Entirety of the mechanism possesses the advantages of compact in structure and rather high amplification efficiency.