Abstract: ： Tobacco variety of 'Longjiang 911' was used as experimental materials, a field experiment was conducted to study the effect of returning ryegrass on agronomic trait, chlorophyll content, photosynthetic characteristics and economic character of flue-cured tobacco. The results showed that the overturning pressure of ryegrass could promote the growth of plant height. The plant height was increased by 21.89%, 14.75% and 10.85% compared with the control（CK2）. The agronomic character and photosynthetic characters were improved, and increased the yield and output value. The output value increased by 5.27%, 24.89% and 2.13% compared with the control （CK2）, thereby improved the economic character of flue-cured tobacco. The agronomic character and economic character of the second batch of flue-cured tobacco were relatively good. Photosynthetic characters are the best for the first batch of conventional fertilization（T1）. There were no significant differences in conventional fertilizers （T1） and reduced fertilizers （T2）, indicating that ryegrass as a green manure may partially replace chemical fertilizers.

Key words: flue-cured tobacco, ryegrass, overturning, fertilization, character comparison