Numerical calculation of pseudo-Brewster angles for substrate and thin-film substrate system is demonstrated. The results show: for only substrates, pseudo-Brewster angles are mainly affected by refractive index when the extinction coefficient is lower than 0.01; when the extinction coefficient is above 0.1, the pseudo-Brewster angle is also modulated by the extinction coefficient. The studies indicate: for thin film-substrate systems, pseudo-Brewster angle is influenced by both refractive index and physical thickness of thin film together with optical constants of substrate; in the HfO2 film on silicon and fused silica substrate systems, pseudo-Brewster angles exhibit quasi-periodic characteristic with variation of incident wavelength or thin film thickness, as caused by interference effect.