Chemical properties of soils and flue-cured tobacco leaves from low-latitude and high-elevation Qujing City of Yunnan Province were measured and Classification Tree Model was used to explore the relations between S and Cl- contents in tobacco leaves and soil various properties. The results showed that: (1) S content in tobacco leaves ranged from 0.07-0.97 mg/kg with a mean of 0.26mg/kg, which was more suitable level but with a great variation. Soil available S content was the uppermost factor affecting S content in tobacco leaves, soil available Ca, altitude, soil rapid available P, pH, organic matter and rapid available K were direct or indirect influential factors. S content in tobacco leaves was mainly affected by soil available P when soil S content was ≤35.53 mg/kg, was mainly affected by soil available Mg when soil S content ranged from 35.53 to 71.83 mg/k and then was mainly affected by soil pH when soil S content ≥71.830 mg/kg. (2) Cl- content in tobacco leaves ranged from 0.20-34.70 mg/kg with a mean of 2.49, with a great variation. Soil water-soluble Cl- content was the primary influential factor of Cl- content in tobacco leaves and the content cut-points were 4.97, 28.48 and 51.93mg/kg respectively. Soil available Mg, rapid available P and Ca also affected Cl- content in tobacco leaves to various degrees.