Abstract: The physiological character between sweet corn and normal corn during seed-seedling transformation was compared and analyzed. The results showed that both starch content of endosperm and fat content of scutellum (except for 0~2 d) decreased. Endosperm starch content of sweet maize was lower than normal corn notably. The activities of starch hydrolytic enzyme and protein hydrolytic enzyme showed a single peak curve. The activity of fatty hydrolytic enzyme decreased. Enzyme activities of sweet corn were lower than those of normal corn at the prophase of seed-seedling transformation, and the differences were not significant at the anaphase. Therefore, storage substance and enzyme activities at the prophase of seed-seedling transformation were the important factors which limited seed-seedling transformation of sweet corn.