In this article, we investigate about stochastic properties of a thin film such as aluminum thin film that is formed by thermal evaporation in high vacuum. So we prepare thin films with different thicknesses on glass surfaces in high vacuum chamber with 10 −6 torr. Then, we use Atomic Force Microscopy (AFM), for determining the height fluctuations of aluminum thin films in different growth stages and use an inverse method that utilizes data from AFM to construct a simple equation that governs the stochastic process and a relation between stochastic parameters such as roughness, correlation and Markov length, drift, and diffusion coefficients during the growth process. Also we show that aluminum thin films, during growth by evaporating in high vacuum chamber, have a mono fractal behavior in small distances(little than 100 nm) on the surfaces.