Abstract:[Objective] Objective of this study was to study the effects of different biochar additions on the physical and chemical properties and tobacco growth, yield and output value in the yellow loam soil of mountain Chongqing region. [Methods] Flue-cured tobacco K326 was used as the experimental material. In 2022-2023, a completely random design was adopted in the tobacco field, and 7 biochar addition treatments were set up based on conventional film ridge cultivating and fertilization methods. The 7 biochar addition treatments were: zero biochar addition (CK), 750 kg/hm2 (T50), 1500 kg/hm2 (T100), 3000 kg/hm2 (T200), 4500 kg/hm2 (T300), 6000 kg/hm2 (T400) and 7500 kg/hm2 (T500). During the studied periods, soil physical and chemical properties and tobacco agronomic traits, ground and above ground dry matters, yield and output value were measured. [Results] The results showed that:(1)the application of biochar reduced soil bulk density and increase soil porosity and capillary water capacity. The differences in soil porosities and capillary water capacities under T400 and T500 treatments and CK treatment were significant, while the rest treatments did not significantly change soil physical properties compared to CK treatments in the second year; (2) compared with CK treatment, biochar addition significantly increased the content of available nitrogen, available phosphorus and available potassium in the 0-20 cm soil profile, and T300, T400 and T500 treatments significantly increased organic matter content and pH value in the 0-20 cm soil profile, which could effectively alleviate soil acidification; (3) compared with CK treatment, T300, T400 and T500 treatments significantly promoted the growth and biomass accumulation of tobacco and significantly increased the yield and output value of tobacco leaves. Considered the input-output ratio, T400 treatment was optimal biochar addition methods for improving soil physical and chemical properties and tobacco yield and output value. [Conclusion]Therefore, adding suitable biochar to tobacco fieldsoil can improve soil physical and chemical properties, increase soil cultivability, promote the growth, development and dry matter accumulation of tobacco plants, and finally increase the yield and output value of tobacco leaves.