Substituted yttrium iron garnet (Bi, Al:YIG, BixY3-xAlyFe5-YO12) were prepared by sol-gel process. Nitrates of bismuth, aluminum, yttrium and iron were used as the starting materials. The highly oriented thin film was obtained on a substrate of gadolinium gallium garnet (GGG) single crystal. The square type ratio (magnetization of the plane perpendicular to the magnetic field (σS(⊥))/magnetization of the plane parallel to the magnetic field (σS())) of the thin film, preferentially oriented in the perpendicular plane as a result of the Al substitution for the iron at the Fe site, exhibited a very large value, greater than 3.5. The Faraday rotation angle (θF) was 50°/μm for the Bi2YAl0.4Fe4.6O12 film.