To meet the demands for screening sweet potato tubers for bioethanol production, 12 genotypes of sweet potato tubers were collected from Henan, Shandong, Anhui, and Jiangsu Provinces, China. Based on the optimized determination method of the percent dry content, the nutritional composition and fermentation properties were studied. There were differences in the compositions and their correlations among the sweet potato varieties. The results showed that the starch content was weakly correlated with other ingredients, while the percent dry content and fermentable sugars contents had a close correlation with starch content. The percent dry content significantly and positively correlated with the flour and fermentable sugars contents. The percent dry content and starch contents had a significantly positive correlation, with a correlation coefficient that reached 0.96.