Tre vapor-solid phase transition of the motybdenum oxide was investigated in the stochastic nonlinear system which was in far from equilibrium state. Some thin molybdena crystals and various two-dimensional fractal structures consisted of the molybdena whiskers were ob-served. The possible mechanism of the fractal structures is discussed in terms of nonequilibrium thermodynamics of irreversible processes and a nucleation aggregation model is proposed.