tIn this paper, the interference pattern of reflected light from a biaxial anisotropic thin film(with arbitrary orientation of the principal optical axes) is numerically investigated by adouble-reflection approach. The pattern for different film thicknesses under illumination ofmonochromatic and white light with various polarizations in different angles of incidenceis obtained. Comparison with isotropic thin films reveals that a kind of modulation (orbanding) appears on the interference pattern.