Cr2O3 is not only a promising functional material, but also an essential barrier to protect chromia-forming alloys against high temperature corrosion. The Cr2O3 protecting layer grows slowly via defect-mediated diffusion. Several types of point defects could be responsible for the diffusion process depending on the oxidation environment, resulting in different semiconductor characters of chromia. According to the literature, the defect chemistry of Cr2O3 in the antiferromagnetic (AFM) state has been well studied using density functional theory (DFT) calculations but not in the paramagnetic (PM) state, which is the fundamental state of Cr2O3 above 318 K. PM Cr2O3 is simulated in this study using special quasi-random structures (SQS). The formation energies of intrinsic point defects in AFM and PM Cr2O3 are calculated to study the defect chemistry and the semiconductor properties in different oxidation environments (temperature and oxygen partial pressure PO2) using a thermodynamic model. It is found that O vacancies and insulating-type Cr2O3, in which commensurate electrons and holes are dominant before atomic defects are more favorable at high temperatures and at low PO2, while Cr vacancies and p-type Cr2O3 are more favorable at low temperatures and at high PO2, according to the calculations both in AFM and PM Cr2O3. However, the limits of dominant zones for defects and for semiconductor characters shift to higher temperatures or lower PO2 in PM state calculations.