In order to study the technological conditions to prepare Cr₇C₃, the carbonization products of Cr₂O₃ were analyzed from the aspects of thermodynamics and the thermodynamic simulation of Cr₇C₃ was carried out by method of standard reaction thermal effect calculation. The effects of reaction temperature, reaction atmosphere and material ratio on the preparation of Cr₇C₃ were studied, and the principle of high purity Cr₇C₃ prepared by carbon thermal reduction method from the melt was explained. The results show that minimum formation temperature of Cr₇C₃ is 1368 K, the increase of the reaction temperature helps to increase the yield of Cr₇C₃; Lowering the CO partial pressure of the system is beneficial to reduce the initial temperature of the reaction and the formation of Cr₇C₃; Cr₇C₃ can react with C in the system to generate Cr₃C₂. Meanwhile increasing the reaction temperature and optimizing the material ratio are conducive to inhibit the excessive carbonization of Cr₇C₃.