Soil air capacity is very important to growth and quality of tobacco. In soils poor in air capacity, tobacco has its leaves expanding slowly at its early growth stage and getting thickened and inadequately expanded at its late growth stage because of continuous nitrogenrelease from the soil, thus seriously affecting quality and flavor of its flue-cured leaves. 【Objective】 This study was oriented toinvestigate soil air capacity of the tobacco-planting areas typical of Yunnan Province, and explore relationshipof soilaeration porosity and soil physical properties with tobacco growth and main factors influencing soilaerationporosity so as to find effective ways to improve quality and yield of the tobacco in Yunnan Province.【Method】For this study, field experiments were laid out in three tobacco planting areastypical of Yunnan Province, i.e. in QinglongTown, NingzhouTown of Huaning County, YuxiCity and ZiwuTown in ChuxiongCity. A total of 38 soil samples were collected from the topsoil and subsoil layers of the experimental tobacco fields for analysis of basic physico-chemical properties, including soil texture, soil bulk density,soil organic matter(SOM) and total nitrogen(TN) contents,pH and so on. Soilaeration porosity of the soil samples was measured with the sand–kaolin box method. Variance analysis and correlation analysis were performed of the obtained data to explore relationshipsof soil aerationporosity with soil physico-chemicalproperties. In the end, a soil aerationporosity prediction model was established based on transfer function of the soil physico- chemicalproperties.【Results】Results show that in line withthe USDA standard for soil texture classification, the soil samples collected from the three areas were dominantly of clayey loam in soil texture, making up about 40% of the total, then of loam and the least of silty loam, which accounted only for 7.9% of the total; bulkdensity of the soils in the three areasvaried from 1.3 to 1.5g• cm^-2, a suitable range for tobacco growth in Yunnan Province; soil organic matter (SOM)content and soil nitrogen supply capacity were high enough to meet the nutrient needs of tobacco for growth and to ensure quality and yield of the crop;and soil aeration porosity was found in the range of 5.9%-15.1%, being on the low side as whole for the areas and varied quite much spatially between areas, with the one in Qinlong Town being the highest, at about 15.1%, which was followed by the one in Ningzhou Town and then the one in Ziwu Town, the lowest at about 9.4%, which is obviously inadequate to meet the need for cultivation of high quality tobacco.Correlation analysis shows that aeration porosity in tobacco-planting soils is mainly affected by silt and clay contents and ultra-significantly and positively related to silt content and negatively to clay content. Consequently, soil aeration porosity can be roughly estimated based on silt and clay contents in the soil.【Conclusion】The soils in the tobacco planting areas of Yunnan are mainly of loam and clayey loam in texture, and their soil bulk densities and nutrient contents are suitable for growth of flue-cured tobacco. But their soil aeration porosities are apparently inadequate for healthy growth and flavor development of tobacco.Soil aeration porosity is significantly related to silt and clay contents in the soil. Therefore, it is recommended that tobacco should be cultivation in soils, loam or sandy loam in texture, where high soil air capacity is available for healthy growth of quality tobacco. The findings in this study may serve as reference for local governments in zoning for cultivation of flue-cured tobacco.