This paper reported an improved PZT95/5 sol-gel preparation method, which with separated lead acetate trihydrate, zirconium nitrate, and titanium butoxide precursor-monomer. The PZT95/5 sol-gel precursor was prepared by these three stable-separated precursor-monomers and some chelating agents. It was deposited onto Si substrate by spin-coating. Researches were carried out on the film structure and dielectric properties associated with water content, sol-gel precursor content and processing techniques. After the precursor solution prepared successfully, a very large dielectric constant, strong stability and fine relaxation of PZT95/5 ferroelectric-films were obtained, whose dielectric constant was 449 at room temperature and changed flatly before 180°C . The peculiar permittivity reached 3446 occurred at the curie temperature (240°C ). The εr-T plots with different frequencies conformed to the material properties of relaxor ferroelectrics, and also the sample had longer relaxation time confirmed by Cole-Cole plots.