Aiming at the problems of shallow plough layer，small capacity of soil bank and poor performance of water and fertilizer conservation in mountain tobacco field，the effects of different plough layer amplification techniques on improving plough layer structure，expanding soil water and nutrient storage capacity，promoting the development of flue-cured tobacco root system and improving the yield and quality of tobacco in mountain tobacco field were studied，and the suitable plough layer amplification techniques for tobacco production in mountain were selected.In 2018，field experiment were carried out in Yuxi，Yunnan province.Flue-cured tobacco ‘K326’ was used as the research material.Four treatments，rotary tillage 20 cm (RT 20，control)，deep tillage 30 cm (DT 30)，deep loosening 30 cm (ST 30) and deep loosening 40 cm (ST 40)，were used to study the effects of different tillage methods on soil nutrient storage capacity，spatial distribution of water and nitrogen and morphological characteristics of flue-cured tobacco root system.The results showed that compared with the control rotary tillage (RT 20)，deep tillage and subsoiling significantly increased the yield and output value of flue-cured tobacco.The yield was increased by 12.2%，12.3% and 16.0%，meanwhile the output was increased by 10.5%，13.9% and 21.8% by the DT 30，ST 30 and ST 40 treatments，respectively.Deep tillage and deep loosening significantly increased the thickness of tillage layer and the total capacity of available nutrient pool in tobacco field.The thickness of tillage layer in DT 30，ST 30 and ST 40 treatments increased by 50.4%，40.8% and 93.2% respectively，and the total capacity distribution of available nutrient pool was 17.7%，26.1% and 34.9% higher than that of the control.The root distribution and soil water content of flue-cured tobacco in 20～40 cm soil layer were significantly increased by deep tillage and deep loosening.The root length and density of DT 30，ST 30 and ST 40 treatments were 36.2%，39.1% and 59.6% higher than that of the control，respectively.The root surface area was 73.0%，103.6% and 86.9% higher than that of the control，and the root volume was 75.6%，54.4% and 86.2% higher than that of the control，and the moisture content was 6.3%，5.3% and 7.9% higher than that of the control，respectively.Nitrogen in 0～50 cm soil layer of DT 30，ST 30 and ST 40 decreased by 7.7%，9.7% and 11.1%，respectively，compared with the control RT 20.The results showed that deep tillage and deep loosening measures could effectively increase the thickness of topsoil layer，significantly increase the effective nutrient storage capacity of topsoil layer，and coordinately optimize the spatial distribution characteristics of root system，soil moisture and soil total nitrogen of flue-cured tobacco，and significantly increase the yield and output value of tobacco.In the future，agricultural machinery and agronomic integration combined application technologies with small-scale deep tillage and subsoiling machinery should be paid attention to，and be promoted according to local conditions.