  Due to the low dimensionality in the quantization of the electronic states
and degree of freedom for device modulation, two-dimensional (2D)
ferromagnetism plays a critical role in lots of fields. In this study, we
perform first-principles calculation to investigate the ising ferromagnetism
and half-metallicity of kagome V$_2$O$_3$ monolayer. Based on the calculations
using different functional, it is found that GGA-PBE gives a half-metallic band
gap while the GGA+U gives a semiconductor narrow band gap (~1.1 meV), which
shows quasi-half metallic nature. By studying the magnetic properties with LDA,
GGA-PBE, and GGA+U, we get a robust ferromagnetic ground state, where the giant
perpendicular magnetic anisotropy energy of ~0.544 meV is achieved by applying
the spin-orbit coupling (SOC) with GGA+U. Furthermore, by exploring the orbital
contribution to the electronic bands and the magnetic crystalline anisotropy,
it is uncovered that the 3d (V) orbitals contribute to the out-of-plane. The
electronic band structure shows two flat bands (F1 and F2) and Dirac points (D1
and D2) which further confirm that kagome V$_2$O$_3$ ML can also be used for
topological properties. Besides, the Curie temperature of the V$_2$O$_3$ ML is
calculated to be 640 K by Metropolis Monte Carlo (MC) simulations.
