PZT thin films with amorphous PZT layer inserted between the film and $Pt/Ti/SiO_2/Si$ substrate were deposited by rf magnerton sputtering. The effect of an amorphous layer on electical characteristics was investigated comparing with the sample without amorphous layer. Insertion of amorphous layer was found to exert marked effects. The sample without amorphous layer form an ohmic contact between platinum and PZT. Barrier contact was formed in the interface between platinum and amorphous PZT. The sample with erpovskite PZT(180nm) and amorphous PZT(20nm) has 800 fo dielectic constant and $3{ imes}10^-7;A/cm^2$ of leakage current.