Abstract: By the combination of Atomic Force Microscope and lock-in amplifier,local piezoelectric properties in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films at different polarized states were studied.The results indicate that,at the negatively polarized state,the vibrations on film surface are linearly dependent on the driving voltage,while,at the positively polarized state,the vibrations are also linearly dependent,but with a phase delay of 180o.The coexistence of the local vibratory domains,non-vibratory domains and vibratory domains with much smaller amplitudes is obviously observed.It is regarded that the existence of in-active ferroelectric domains should be contributed to the origin of non-vibratory domains and these in-active domains are pinned by trapped charges.