A series of highly ordered mesoporous Cr2O3 were prepared through the nanocasting pathway from decomposition of chromium(VI) oxide using KIT-6 as a hard template. The effects of the calcination temperature on the crystal structure, textural parameters and magnetic properties of the material were investigated. It was found that with increasing calcination temperature, surface area and pore volume of the mesoporous Cr2O3 decreased slightly. Unpredictably, increasing calcination temperature also influences the lattice parameters of the Cr2O3 crystal, and this rearrangement in the lattice parameter leads to changes in the value of the Neel temperature. A spin-flop transition has been observed at a magnetic field smaller than that of bulk material.