Abstract: In order to reduce nitrogen application rate and increase nitrogen utilization efficiency of flue-cured tobacco, a field experiment was carried out by taking flue-cured tobacco cv. Honghuadajinyuan as an experimental material. Chitooligosaccharide solutions at four concentrations(0, 80, 105 and 130 mg/L)were sprayed on tobacco plants on the 30th, 40th, 50th and 60th days after transplanting, respectively. The effects of chitooligosaccharide spraying on the nitrogen utilization efficiency and quality of flue-cured tobacco were studied. The results showed that the growth potential, yield and quality of flue-cured tobacco deteriorated when nitrogen application rate was reduced without spraying chitooligosaccharide. The treatments of reducing 20% nitrogen fertilizer and spraying chitooligosaccharide promoted the growth of tobacco before topping, increased the absorption of nitrogen and nitrogen utilization efficiency; and the promotion effects became more obvious with the increase of chitooligosaccharide concentration. Under the treatment of 20% nitrogen fertilizer reduction and spraying 105 mg/L chitooligosaccharide, the proportion of high grade leaves and sensory quality were better than those at conventional nitrogen application rate(the control). Comparing with the control, the output value, apparent nitrogen utilization efficiency and agronomic utilization efficiency of flue-cured tobacco increased by 26.33%, 39.33% and 61.02%, respectively. Therefore, under the condition of reducing nitrogen application rate, spraying chitooligosaccharide solution at early growing stage has significant promotion effects on the quality and nitrogen use efficiency of flue-cured tobacco.