Abstract: This study was conducted in major tobacco-growing areas of Sichuan Province, where soil samples were collected from 296 fields. The mechanisms of continuous cropping duration on soil hardness and its key influencing factors were systematically analyzed, and the effects of soil hardness on tobacco leaf economic traits were explored. The results showed that with the increase of continuous cropping duration, soil hardness significantly increased. The soil hardness in fields with 16~20 years of continuous cropping was approximately 27.02% higher than that in fields without continuous cropping. Random forest model analysis revealed that the contribution rates of soil large aggregates, bulk density, and alkaline nitrogen to soil hardness were 20.52%, 15.46%, and 13.22%, respectively. Mediation effect analysis indicated that continuous cropping duration indirectly aggravated soil hardening through mediation variables such as bulk density, silt, organic matter and alkaline nitrogen, with the positive mediating effect of bulk density being the most significant (path coefficient = 0.35). The economic traits of tobacco leaves were the best under low soil hardness.