A total of 943 yellow earth samples were collected from 9 major flu-cured tobacco production regions in Guizhou for analysis of nitrogen (N0) using the Stanford intermittent leaching-aerobic incubation method, and of the soil samples, 93 typical ones were picked for determination of mineralization rate constant. Results show that of the soils the nitrogen mineralization rate constants averaged 0.031 mg kg^-1 d^-1, and the nitrogen mineralization potential averaged 92.8 mg kg^-1, and varied sharply from region to region in the range of 10.2~280.5 mg kg^-1. The potential was 103.5, 90.6, 71.0, 116.2, 91.1, 89.0, 79.6, 84.6 and 99.6 mg kg^-1 for for the soil of Anshun, Bijie, Guiyang, Liupanshui, Southeast Guizhou, South Guizhou, Southwest Guizhou, Tongren, Zunyi, respectively. Of the 9 tobacco growing regions of Guizhou, the potential N supply capacity was relatively low in the center of the province, and increased gradually towards all directions geographically, and turned out to be a bit too high in some regions in Liupanshui and Southeast. The potential N supply capacity of yellow earth was found to be positively related to the content of organic matter. It is, therefore, feasible to make primary assessment of nitrogen mineralization potential of tobacco-growing yellow earths using the exponential function model. The macroscopic knowledge of the potential nitrogen supply capacity of the tobacco-growing yellow earths in Guizhou will help provide a sound basis for rational arrangement of flu-cured tobacco cultivation in the Province.