The uniform Sr0.5Ba0.5Bi4Ti4O15 thin films were prepared using a modified Sol-Gel technique and the influence of precursor on the microstructure and characterization of thin films were studied. The stability and uniformity of precursor solution is key issue for the quality of thin films. Ethanolamine is an effective complexation reagent of Bi3+, which could moderate the acidity of precursor. When pH value and concentration of precursor solution was about 3.5 and 0.35M respectively, the smooth and uniform Sr0.5Ba0.5Bi4Ti4O15 thin films could be obtained. The Bi-layered perovskite structure of Sr0.5Ba0.5Bi4Ti4O15 formed at 750°C. The morphology of the grains in Sr0.5Ba0.5Bi4Ti4O15 thin films was elliptoid and the grain size was about 90 ~ 100 nm.