Abstract: Pot experiments with hydroponics were carried out to study the effect of adventitious root on the chlorophyll content, nitrate reductase activity and the content of nitrogen, potassium, nicotine in K326flue-cured tobacco after multi-topping.The results showed that the chlorophyll content, nitrate reductase activity and the content of nitrogen, potassium, nicotine were greatly enhanced after adventitious root induced by flower mud.It indicated that adventitious root could absorb more nutrients and promote growth of tobacco.Comparing with other treatments, the effect of adding nutrient solution directly to the flower mud was the best, especially in the chlorophyll content, nitrate reductase activity and the content of nitrogen, potassium from cultured plants, and the content of nicotine was appropriate.