Abstract: To improve floating seedling system for tobacco, tobacco seedling culturing experiments were conducted in a floating system with in-house designed novel ventilated seedling tray. By taking common seedling tray as a control, the effects of ventilated seedling tray on the emergence rate, botanical characters and activities of protective enzymes and nitrate reductase (NR) of tobacco seedling were studied. The results showed that comparing with the control, the time of seedling culturing in the ventilated seedling tray was shortened by 5 d and emergence rate increased by 3.67%; the leaf size, root development and comprehensive growth of tobacco seedlings were significantly improved. On the 35th, 45th and 55th days after sowing, the root vigor of seedling increased by 14.26%, 20.45% and 19.31%, respectively; chlorophyll contents and the activities of catalase, peroxidase, superoxide dismutase and NR significantly increased comparing with the control. Therefore, the novel ventilated seedling tray has shown a clear promoting effect on seedling growth.