Backscattering technique is employed for analysis of thin carbon and aluminum films which are prepared by vacuum evaporation. The alpha particles are accelerated by Van de Graaff accelerator to 2MeV and incident to the thin film whose thickness is less than 2000 Å. The scattered alpha particles are detected by a silicon surface barrier detector which is set at 160” relative to the incident beam direction. The spectrum is analyzed to trace elements containing in the thin film. Quantitative calculation is also made.