Grades, appearance quality, main chemical components and smoking quality of tobacco (cultivar Yan’an No.1) middle and upper leaves cured in the lower layer, middle layer and upper layer of air descending bulk curing barn were investigated with the process in which the yellowing stage was turned to color fixing stage at the point when the leaves in each layer turned yellow with green main vein and the main vein of leaves turns soft. Results showed that there were large differences in yellow degree in leaves from lower layer, middle layer and upper layer of the bulk curing barn. For middle leaves after curing, the proportion of superior grade leaves from the middle layer of the barn was the highest, which was respectively 15.9% and 23.4% higher than those cured in the upper and lower layer, and the appearance quality, the coordination of main chemical components and smoking quality of these leaves were the best; the proportion of slightly green leaves from the upper layer was high; and the proportion of variegated tobacco from the lower layer was high indicating the leaves were over yellowed. For upper leaves after curing, the proportion of superior grade leaves from the lower layer of the barn was respectively 47.4% and 20.7% higher than those from the upper layer and the middle layer; starch content in these leaves from the lower layer was 12.6% and 5.7% lower than that from the upper layer and the middle layer, respectively; and the coordination of main chemical components and smoking quality of these leaves were the best.