A novel aqueous chemical solution was developed as a precursor both for LiNbO3 powder and thin film. In this method, hydrogen peroxide aqueous solution (H2O2) reacts with niobium and lithium alkoxide ethanol solution to form metal peroxide aqueous solution. From this solution, crystalline LiNbO3 were synthesized at a temperature as low as 350°C. LiNbO3 thin films with well-developed grains were fabricated by spin-coating on silicon and sapphire substrates. In comparison with the alkoxide solution method, this peroxide solution method provides significant advantages, such as low weight loss in the sintering process and easy handling.