Abstract: To determine the effect and appropriate depth of smashing ridge tillage in tobacco-planting soil, 4 treatments including 30 cm, 40 cm, 50 cm depth of smashing ridge tillage and traditional cultivation were designed to analyze the dynamic changes of roots and above ground growth of flue-cured tobacco, and to study the effects of smashing ridge tillage on accumulation and distribution of dry matter, nitrogen, phosphorus, potassium, nicotine and chlorine of flue-cured tobacco, as well as economic properties and chemical composition of flue-cured tobacco. The growth of tobacco roots and aboveground parts could be promoted by smashing ridge tillage. Increasing the depth of smashing ridge tillage is favorable for tobacco roots to grow down. Smashing ridge tillage is beneficial to the accumulation of dry matter, nitrogen, phosphorus, potassium, nicotine and chlorine in flue-cured tobacco. The accumulated dry matter of flue-cured tobacco was mainly distributed to tobacco leaves, and the smashing ridge tillage depth of 40-50 cm was beneficial to the distribution of dry matter, nitrogen, phosphorus and potassium to the tobacco root, while the smashing ridge tillage depth of 50 cm was beneficial to the distribution of nicotine and chlorine to the tobacco root. Proper depth of smashing ridge tillage is beneficial to increase yield and output value of flue-cured tobacco. Smashing ridge tillage can increase potassium content in tobacco leaves, as well as increase nicotine and chlorine contents in tobacco leaves. Smashing ridge tillage could be adopted to improved tobacco-planting soil in mountainous areas, with the best depth of smashing ridge tillage being 40 cm.