The characteristics of nonvolatile organic acids in Hubei flue-cured tobacco and its relationship with altitude were analyzed. The results indicated that the contents of nonvolatile organic acids averaged 139.62 mg/g, and in grades from high to low was X2F>C3F>B2F. The ratio of reducing sugar to nonvolatile organic acids was suitable in whole. Altitude and nonvolatile organic acids, the ratio of reducing sugar to nonvolatile organic acids could be classified into three groups by cluster analysis. In the leaves of B2F and C3F at the altitude of 950-1150 m, and X2F at 1050-1300 m, the contents of nonvolatile organic acids were higher and the ratio of reducing sugar to nonvolatile organic acids was favorable.