Abstract: The curing quality of burley tobacco depends on characteristics of fresh leaves and the natural environment conditions, at the same time closely linked to the degree the leaves wilt in the field. The effect of different duration for the leaf wilt in the field on water loss of the whole plant, the color change, the speed of drying and the quantity and quality of the leaves were studied, The results showed that the wilt and water loss in the field for several days, not only could reduce the water drainage pressure in the curing barn, increase the buffering effect on adverse conditions and ensure the curing going on smoothly, but also could quicken the water loss, the colour changing and drying and shorten the duration of curing. Adequate wilt and water loss imposed good influence on reducing the consumption of internal contents, increasing weight per leaf and improving the taste and external quality of the leaf, The best conditions for the wilting are:a. under the precondition of avoiding the sun scorch; b. the rate of water loss should ranges between 15% -20% ; c. the mid-rib and lateral vein of lower position leaves become sofetened; d. the lateral vein of middle leaves softened somewhat; e. the mid-rib softened a little; f. the laminas of upper leaves softened and the lateral vein a little softened.