Ba 0.65 Sr 0.35 TiO 3 (BST) thin films were deposited on Pt/Ti/SiO 2 /Si, RuO 2 /SiO 2 /Si and RuO 2 /Pt/Ti/SiO 2 /Si substrates by radio frequency magnetron sputtering technique. The effects of these bottom electrodes on the microstructure and dielectric properties of the BST thin films were investigated by using X-ray diffraction (XRD), atomic force microscope (AFM), transmission electron microscopy (TEM) and electrical measurements. The BST thin films on RuO 2 /Pt hybrid bottom electrodes exhibit good crystalline and interfacial structure with a thinner transition layer. Dielectric measurement reveals that the films on RuO 2 /Pt hybrid electrodes have comparable dielectric constant and loss tangent with the films on Pt electrode, and the dielectric tunability of BST films on RuO 2 /Pt reaches 38.2%, which is higher than that of BST films on a single Pt or RuO 2 electrode. The BST thin films on RuO 2 /Pt exhibit lower leakage current density by nearly two orders’ of magnitude than that on RuO 2 electrode. The higher tunability and lower leakage current of the films on RuO 2 /Pt hybrid bottom electrodes are mainly attributed to the RuO 2 layer, which facilitates the nucleation and growth of BST films, and inhibits the interfacial diffusion between the BST films and bottom electrodes. The results show a potential for RuO 2 /Pt hybrid electrodes replacing Pt electrode in microelectronic device applications.