The invention discloses a conductive thin film and a preparation method thereof. Titanium dioxide sol and nanometer silver wires are prepared into a composite material to prepare conductive ink to besprayed on a PET thin film so as to prepare a flexible transparent conductive thin film. Compared with a single nanometer silver wire thin film, the thin film prepared in the invention has higher conductive performance. The raw materials disclosed in the invention are easily available and relatively low in cost, and the process conditions are simple and convenient, can be performed at the normal temperature, and high in repeatability, so that large-scale manufacturing can be realized. According to actual needs, the conductive thin films of different conductive performance and light transmittance can be obtained by changing the spraying speeds, and the conductive thin film has wide application prospect on a precise optical device and other flexible materials.