Abstract: With different planting density and rate of N application, the tissue structure of burley tobacco leaf was studied by the micro-observation of slice. The results showed that the thickness of leaf, palisade tissue, spongy tissue and upper epidermis, ratios of tissue, thickness of palisade tissue /leaf thickness, and the width of palisade tissue had significantly negative correlation with planting density. The rate of descending in average thickness of leaf, upper epidermis and under epidermis, and the width of palisade tissue increased in the planting density from 15000~18000/hm2 to 18000~21000/hm2. While the rate of descending in average thickness of palisade tissue and spongy tissue, ratios of tissue, and thickness of palisade tissue /leaf thickness descended. But this had significantly positive correlation with rate of N application. The rate of rising in average thickness of leaf, spongy tissue and under epidermis increased at rate of N application from 240~300kg/hm2 to 300~360kg/hm2. While the rate of rising in average thickness of palisade tissue and upper epidermis, ratios of tissue, thickness of palisade tissue /leaf thickness, and the width of palisade tissue descended The effect on the thickness of leaf, under epidermis spongy tissue and upper epidermis, ratios of tissue, and the width of palisade tissue in planting density was higher than rate of N application, but the thickness of spongy tissue was lower. The thickness of palisade tissue /leaf thickness was same. With this result, the planting density of 18000~19500/hm2 and rate of N application from 270~300kg/hm2 was feasible in burley tobacco.