Abstract: In order to optimize the curing technology of the standardized intensive curing barn,and explore the best curing temperature and humidity combination, the sets of temperature and humidity combinations tests were conducted. That was the upper, middle and lower leaves of the K326 flue-cured tobacco varieties used as test materials at the yellowing stage to study the effect of water loss rate,chlorophyll degradation rate, and economic traits of tobacco leaves with the temperature in 30~48 ℃ and relative humidity in the 70%~85%. The results showed that when temperature and humidity were too higher or too low at the yellowing stage, or the water loss rate and yellowing of tobacco leaves were uncoordinated, it was easy to produce bad tobacco leaves; the chlorophyll degradation rate of different parts of tobacco leaves was less affected by the temperature and humidity during the yellowing stage; the lower leaves had the best economic traits with temperature of 38 ℃ and relative humidity of 80%,and the superior proportion, the mid-superior proportion and the average price were 50.35%,83.88%,and 31.57 yuan/kg, respectively; the middle leaves had the best economic traits with temperate of 38 ℃ and relative humidity of 75%, and the superior proportion, the mid-superior proportion and the average price were 53.53%,89.25%, and 33.76 yuan/kg, respectively; the upper leaves had the best economic traits with temperature of 40 ℃ and relative humidity of 75%,and the superior proportion, the mid-superior proportion and the average price were 56.23%, 88.91%, and 34.09 yuan/kg, respectively.

Key words: K326, curing process, water loss rate, chlorophyll degradation rate, economic traits