Bismuth is a half metal having anisotropic susceptibility and optical constants. Therefore, the crystal axis of bismuth particle can be oriented by magnetic torque under magnetic fields. Recently, bismuth nano-particles, which have spherical, plate-like and rod-like shapes, have been prepared by some chemical methods. Orientation of bismuth nanospheres in a viscous liquid was demonstrated by using in-situ observation system of x-ray diffraction under high magnetic field in this study. The anisotropic susceptibility determined from the orientation behavior was slightly smaller than that of the bulk bismuth crystal. We have successfully introduced oriented-bismuth nano-spheres into the transparent polymethyl metacrylate under high magnetic fields up to 8 T. The composite showed a difference in transmittance depending on the direction of propagation of light being parallel or perpendicular to the applied field, indicating an anisotropic nature of optical constants of the nano-particles. Transmission spectra, which were simulated on the nano-spheres oriented composite by rigorously coupled wave analysis (RCWA), indicated that the nano-sphere has larger anisotropy in optical constants than bulk bismuth.