Abstract: The reationship between chlorine and potassium nutrition in plant and the yield and quality of flue-cured tobacco was studied. The results showed that Cl-supply, at the rate of 80-240 mg Cl/kg soil, enhanced photosynthesis, POD,PPO,SOD and NR activity, and increased leaf area, thus increased the yield of cured leaf. With the increase of Cl rates, the Cl content in tobacco leaves increased. The magnitude order of Cl contents in flue-cured tobacco plant parts was leaf stem root, and that in leaves at different positions was lowermiddleupper. When Cl was applied at 0-320 mg Cl/kg soil, the content of Cl in middle leaf were 0.376-2.674%, the K2O/Cl ratio was 8.3-1.4. Based on the requirement for high quality tobaco (Cl content in leaves