Abstract: In order to study the effect of water supplying on the growth and development of tobacco plant, yield and quality, water supplying regulation was tested during different growth and development period of flue-cured tobacco. The results showed that watering when the moisture content in soil was lower than drought index, the proportion of high grade leaves, yield and output value would be higher than the contrast;tobacco plant was stronger, the contents of nicotine, total nitrogen and protein in tobacco leaves were lower by irrigating in early growth stage.As the irrigating time advanced, the potassium content in tobacco leaves raised gradually, the chemical components were more harmonious, and smoking quality was improved as well.