To investigate the effect of biochar application on tobacco, pot experiments were conducted to study the impacts of applying straw biochar at different levels on tobacco growth and soil nutrients. The results showed that the growth of above-ground organs of tobacco was promoted by biochar application in the soil at moderate levels (0.2-1.0%) while inhibited by high level (5%) biochar application. Compared with the above-ground parts, the growth of the root system was promoted by biochar application at all levels tested, with the 5% biochar treatment resulting in the highest root/shoot ratio. This treatment also delayed the aging of the root system including lateral roots. The length of primary roots, first and second-order lateral roots and the root/shoot ratio of tobacco plants increased at early stages then decreased at late stages of development in all treatments. Moreover, with the increase of biochar application level, soil bulk density decreased while an increase was observed in soil pH and soil nutritional indicators including Organic carbon, alkali-hydrolysable nitrogen, available P and rapidly available K, with the soil nutrient level reaching the highest in the 5% biochar treatment. Our results suggested that biochar application in tobacco fields at appropriate levels (0.2-1.0%) would lead to an increase in soil nutrients and promote tobacco growth. Further field studies are needed to test the effect of biochar application in different types of soils with various physical and chemical properties.