Abstract: The growth and development of field flue-cured tobacco under different nitrogen levels were studied.The results indicated that different nitrogen levels had no effects on leaf-emerging rate and total leaf-emerging numbers except no nitrogen application;leaf area coefficient、maximum leaf area and yield of dry matter in the above-ground parts increased steadily as nitrogen levels increased, tobacco over-growth due to nitrogen excess began mainly from later vigorous growth stage;dry matter accum ulation ratios of tobacco were 15%、60% and 25% respectively in early vigorous growth stage、vigorous growth stage and mature stage, economic coefficient was about 75% under the proper nitrogen level (6 kg N/mu).