We report relationship between the degrees of tri-axial orientation and doping level of rare earth (RE) ions in Bi 2 Sr 2 (Ca 1− x RE x )Cu 2 O y (RE-doped Bi2212; RE=Dy, Ho, Er and Tm) powder samples aligned under a modulated rotation magnetic field (MRF) of 10T. Tri-axial magnetic alignment of the RE-doped Bi2212 with x=0–0.5 was achieved by single-ion magnetic anisotropy of RE 3+ and tri-axial magnetic anisotropy induced by modulation microstructure in a grain level. The degrees of in-plane and c-axis orientation with ∼3° were achieved for the case of the Tm-doped Bi2212 with x=0.5. The findings in the present study give us important information for the fabrication of triaxially oriented Bi-based cuprate superconductor materials by the magneto-scientific process.