A Separated Spin Evolution Quantum Hydrodynamics Model is employed to investigate arbitrary amplitude ion‐acoustic waves in magnetized plasma, which consists of inertia‐less degenerated electrons with spin‐up n↑$$ {n}_{\uparrow } $$ and spin‐down n↓$$ {n}_{\downarrow } $$ states, as well as inertial classical ions. In a two‐dimensional plasma geometry, a homogeneous magnetic field is assumed to be directed along the z‐axis, that is, boldB=B0truez^$$ \mathbf{B}={B}_0\hat{z} $$. In the linear analysis, two branches of waves propagation are found to occur in the oblique direction. The characteristics of large‐amplitude ions solitary waves propagation in oblique direction are studied through an energy‐balance equation, by applying a Sagdeev potential approach. The parametric role of the spin density polarization ratio κ$$ \kappa $$ on the properties of solitary wave structures, as well as other important plasma parameters, is traced analytically. The scope of our work is significant to study dilute magnetic semiconductors, magnetosphere, and as well as astrophysical systems.