Abstract: The treatment conditions and decoloring effect of Fe²⁺ /H₂O₂ system and fluorescent elimination agent were compared, and the influence of treatment conditions on the conversion of Cr³⁺ to Cr⁶⁺ was also investigated. The results show that: 1) the decoloring rate of Fe²⁺ /H₂O₂ system is good with the temperature of 50 ℃, pH = 3, FeSO₄·7H₂O/ H₂O₂ = 2 mg/3 mL, and it is unable to turn trivalent chromium into hexavalent chromium; 2) the decoloring rate of fluorescent elimination agent is fine with the temperature of 50 ℃, pH = 3, but it can turn trivalent chromium into hexavalent chromium.