Growth and structural evolution of La0.5Sr0.5CoO3 thin films fabricated directly on SiO2/Si substrate by pulsed laser deposition were investigated. Films deposited at 780 °C and oxygen partial pressure of 2 Pa showed highly c-axis orientation. Films with low electrical resistivity of 2×10−3 Ω cm were obtained by annealing at 650 °C for 40 min. C-axis oriented Ba0.5Sr0.5TiO3 thin film was then grown on the La0.5Sr0.5CoO3 film, and large dielectric tuning (>50%) was achieved. This method may have good prospect for the integration of ferroelectric materials with conventional Si process technology.