Abstract: An analytical method of measuring carbon in V₂O₃ with infrared absorption carbon-sulphur analysis unit(CS-344) is established through a number of comparative tests, work curve correction and standard addition process. The method and carbon analysis data are reliable through rechecking. Determination results show that relative standard deviation ≤ 7.0% is achieved by accuracy test within the range of 0.02%~0.05% C in V₂O₃. Through a number of tests it is identified that Ammonium salt present and carbon content in V₂O₃ decreased gradually with longer time are major influencing factors on accurate measurement carbon with the infrared method.