With the best regression of two factors, namely temperature and (RH), the authors studied the relationship between tar content, aroma and taste of tobacco leaf with curing environment in yellowing stage of flue-cured tobacco (var. Guiyan4). Results showed that, when the temperature was between 32 oC and 42 oC, and RH between 75% and 95%, as RH increased, the tar content and the aroma and taste of cured tobacco leaves increased gradually at the beginning of curing and decreased when the peak was reached. With the increasing temperature, the tar content decreased first, then increased. But this was opposite for aroma and taste. The temperature of 37- 39℃ and RH of 75% - 80% or 90% - 95% might be favorable for reduced tar content, while enhanced aroma and taste might be produced at the temperature of 37- 39℃ and RH of 83.7% - 90%. It is concluded that there is little possibility to increase aroma content, improve taste, and reduced tar content by controlling curing temperature or RH in yellowing stage.