Abstract: In order to solve the barn fan problem of high air, the circulation fan in the barn dense inverter under the condition of different baking stages was set up different frequency conversion. The result shows that the baking could barn tobacco leaf gap between relatively stable in 0.2-0.5 m/s range, yellowing and fixing color whole time was extend to 10 h, with the external appearance quality improvment, orange tobacco and maturity scale all increased by 7%, and loose degree increased by 4%, the tobacco inner chemical composition improved to total sugar and reducing increased by 1.1% and 3%, respectively. Starch content reduced by 0.7% and smoking taste tested obviously turned better.