Ba 0.65 Sr 0.35 TiO 3 (BST) thin films doped with Ho 3+ were prepared on silicon substrates by a modified sol–gel technique. The microstructure of the BST films was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. The results showed that 3 mol% Ho-doped BST has the largest grain size and surface root-mean square roughness. The thickness of the film was about 1.36 μm. The Ho 3+ luminescence intensity reached a maximum value in the sample with 3 mol% Ho 3+ ions concentration sintered at 700 °C. All the results showed that the BST: Ho 3+ films may have potential use for photonic devices.