In order to promote the high-quality production of tobacco leaves，93 groups of same-field soil and cured C3F grade tobacco leaves were collected in Guizhou Province for the determination of soil nutrients and tobacco leaf sugar/nicotine ratio. The random forest model was used to predict the sugar/nicotine ratio. The importance of variables was evaluated by Boruta algorithm and the minimum data set was constructed to evaluate the quality of tobacco planting soil based on tobacco leaf sugar/nicotine ratio. At the same time，the main limiting factors of sugar/nicotine ratio of tobacco leaves in Guizhou tobacco-growing area were identified. The results showed as follows：（1）According to the Boruta analysis，Cu，B， alkaline hydrolyzed nitrogen（AN），available potassium（AK）and Fe were identified as important factors affecting the sugar/nicotine ratio of tobacco leaves，and constituted the minimum data set for evaluating the quality of tobacco planting soil.（2）The results of tobacco soil quality evaluation based on the full data set showed that the soil quality index（SQI_TDS）ranged from 38.30 to 78.07，with an average value of 60.20，indicating a good overall soil quality. The coefficient of determination between SQI_MDS and SQI_TDS based on minimum data set was 0.66（P＜0.001）. The SQI_TDS grade prediction accuracy of minimum data set was up to 88.17%，and the Area Under Curve（AUC）of Receiver Operating Characteristic Curve values ranged from 0.90 to 0.97，indicating that the minimum data set could effectively replace the full data set to evaluate the quality of tobacco growing soil.（3）Based on the analysis of low-scoring factors in soil quality indices，the main soil-limiting factors for sugar/nicotine ratio in tobacco leaves in Guizhou Province had been identified as Cu，B and Fe，primarily due to their low contents. Consequently，reasonable regulation of Cu，B and Fe contents in the soil during production could be expected to improve the sugar/nicotine ratio and enhance the quality of tobacco leaves.