Abstract: In order to reveal the rules of chlorine absorption and utilization in flue-cured tobacco, a hydroponic experiment was carried out to explore the absorption kinetics of flue-cured tobacco varieties ‘K326’ and ‘Xiangyan 5’ in Hoagland’s nutrient solutions with six different chlorine concentration gradients. The effects of flue-cured varieties, chlorine content in tobacco plant and the chlorine concentration in the medium solution were compared. The results showed that (1) at low to moderate chlorine level (0-0.8 mmol/L), the relationship between root chlorine absorption rate and chlorine concentration accorded with the model of enzyme kinetics; (2) ‘Xiangyan5’ and ‘K326’ showed high affinity and higher absorption rate at low to moderate chlorine level, which indicated that low chlorine level was benefit to chlorine absorption; (3) the absorption potential of tobacco plants with low chlorine content was greater than that with high chlorine content.