Abstract: The effects of various combinations of stable time at key temperatures (38, 42, 46, 47, 54 ℃) and humidity on the appearance, chemical components and economic values of tobacco leaves during bulk curing were studied in order to provide a theoretical basis for optimization and perfection of standardized curing technology by bulk curing barn built in 2011. The result showed that, if the stable time of key curing temperature maintained a long time, with a relatively high wet bulb temperature (38 ℃) and moderate wet bulb temperature since the 42 ℃ of dry bulb temperature, the physical and physiological and biochemical reactions in tobacco leaves were sufficient, both the appearance quality and smoking quality reached the highest, the chemistry compositions of the leaves was harmonize, but the body was somewhat thinner, more variegated leave. Therefore, we should maintenance suitable humidity and control stable time of dry bulb temperature to avoid yellow since 42 ℃ during bulk curing, which can balance flue-cured tobacco leaves quality and efficiency.