The preparation and the microstructure of BaBi4Ti4O15 (BBT) thin films were reported in the paper. BBT thin films were fabricated on silicon substrate using a modified Sol-Gel technique. A key issue of Sol-Gel processing is the chemical reaction and mechanism of precursor solution, which governs the crystallization and characteristics of the final oxide layer. Ethanolamine is an effective complexation reagent of Bi3+, which could moderate the acidity of precursor. When pH value is about 3.5, the stable and uniform BBT precursor solution could be obtained. The Bi-layered perovskite structure of BBT forms at 750°C. The morphology of the grains in BBT thin films is spheroidal and the grain size is about 120nm.