Abstract: The air-curing of burley tobacco at different altitudes and climates were studied with two years experiments, the problems of being dried hastily at low altitude district and barn rot at high altitude district during air curing were effectively solved.The key was to maintain proper relative humidity in curing barn during curing process.At low altitude district, it could be achieved by adding and keeping moisture, which prolonged the curing time by 5-7 days and resulted in an increase of high-middle grade leaves by 7.8 percentage points;at high altitude district, the proper relative humidity in curing barn could be reached by raising temperature and ventilation, which shortened the curing time by 3-4 days and resulted in an increase of high-middle grade leaves by 10.8 percentage points.