Abstract: The conventional flue-curing barn was upgraded by hot air circulation and automation for temperature and humidity.Vertical difference(VD) between air temperatures at bottom and top tiers in the upgraded barns of the size of 4 m×4 m×5.7 m and 2.7 m×2.7 m×5.7 m were significantly smaller,particularly,during color fixing stage it was 3.84℃ smaller than that in conventional barns of the same size,while the VDs in the two upgraded barns showed no significant difference during curing.Horizontal temperature difference(HTD) in upgraded barns was significantly smaller than that in conventional barns,the difference between HTDs in the upgraded barn and conventional barn during stem-drying stage was the biggest(1.06℃,average),while the difference between HTDs in the two upgraded barns was not significant during curing.The leaves cured in the upgraded barns increased average price by 3.33 yuan/kg and ratio of high and middle grade leaves by 27.99%;the weight ratio of fresh to dry leaves and curing cost reduced 2.43 and 0.42 yuan/kg,respectively;the appearance quality of tobacco leaves cured in the upgraded barns improved significantly.