Flue–cured tobacco variety Honghuadajinyuan were used as materials to study the effects of different degrees of root pruning and girdling on leaf thickness, leaf area, SPAD value, photosynthetic characteristics, yield and quality of flue–cured tobacco. The results showed that when root girdling and bilateral root pruning were conducted after the harvest of lower leaves, the leaf area of fresh leaves were increased by 18.01% and 9.29% respectively, compared to the control with no root girdling and pruning; the blades were thinned by 7.20% and 1.88% respectively, which significantly improved the extension level of upper leaves; the SPAD value and net photosynthetic rate decreased rapidly and the leaves matured and turned yellow rapidly; the proportion of medium tobacco increased by 6.73% and 4.75% respectively, and the average price of tobacco was improved by 11.12% and 5.44% respectively, and the economic benefit was improved significantly. Root girdling after the harvest of middle leaves had little effect on upper leaf area and thickness, but significantly promoted the decrease of SPAD value and net photosynthetic rate of the upper leaves, promoted yellowing of the upper leaves, and had little effect on the yield and quality of tobacco. Root pruning on one side improved tobacco resistance, restrained decrease of tobacco net photosynthetic rate, delayed the tobacco harvest time. It was concluded that girdling after lower leaves harvesting can be used as a technical measure to promote the upper leaves yellowing and to improve the yield and quality of tobacco.