Abstract: Zr can not only improve the ductility of Ni₃Al-based superalloy, but also benefit the oxidation resistance of Ni₃Al-based superalloy. However, the mechanism of the oxidation resistance of Zr in superalloy is not clear, yet. First-principle calculation method was used to study the influence of Zr on the occupation behavior of O in Ni-Ni₃Al system with lattice misfit, and to explore the mechanism of the oxidation resistance of Zr in Ni-Ni₃Al alloy system. It is found that the adding of Zr is beneficial to improve the stability of O in the Ni-Ni₃Al system, but has little influence on the site preferring of O to Ni-rich and large-space region; The beneficial effect of Zr on the stability of O is not influenced by lattice misfit in Ni phase but in Ni₃Al phase, and the effect of Zr on the stability of O may change from beneficial to harmful, which causes the segregation of O to Zr-free Ni₃Al region or to Ni-rich region.