(Ba1-xSrx)TiO3 (BST) ferroelectric thin films were fabricated by sol-gel processing, using Ba(Ac)(2), Sr(Ac)(2), and Ti(OC4H9)(4) as starting materials. Differential scanning calorimetry (DSC), backscattering scanning electronic microscopy (BS-SEM), and X-ray diffraction (XRD) were employed to investigate the effect of chelating agents on the phase formation characteristics and microstructure of the BST films. It was found that the chelating agents, acetate acid (HAc) and acetylacetone (HAcAc), changed the crystallization path from amorphous to crystalline phase during annealing. BS-SEM revealed that HAcAc improved the densification and compositional homogeneity in the microregion of the films. These phenomena were explained by the modified condensation property of the precursors.