Abstract: Objective：To investigate the protection of sodium fluoride on the enamel of deciduous tooth from erosion by carbonated beverages. Methods：Seventy-two enamel blocks were made from human deciduous teeth as samples for the study, and were randomly divided equally into three groups, and each group was divided further into two subgroups according to their immersion duration in carbonated beverages (30min or 50min). Samples in experimental group A and B were respectively treated with 0.6% and 1.23% sodium fluoride, while these in control group were without abovementioned managements. Samples of two subgroups were immersed in carbonated beverages (Coca-Cola) for 30 min and 50 min, respectively. After that, the samples were washed with distilled water. And then, the samples were re-immersed in Coca-Cola with same format after the samples in experimental groups were re-treated with the sodium fluoride. Such immersion-wash circling was kept on for 12 h. To assess the resistance, reinforced by sodium fluoride, of enamel of deciduous teeth to acid erosion caused by Coca-Cola, the structural changes on enamel surface were observed with scanning electron microscope. The hardness of enamel was measured by the surface micro-hardness (SMH). Results：Compared to the control, enamel treated with sodium fluorides was more resistant to acid erosion (P<0.05), with the protective effects being commensurate with concentration of fluoride in the foams (P<0.05). As the immersion time in Coca-Cola prolonged, the protection of the foam weakened accordingly. Conclusions：Sodium fluoride could enhance enamel′s resistance to acid erosion caused by carbonated beverages.