Objective To observe the effect of infiltration resin combined with cold light whitening in the treatment of dental fluorosis. Methods According to the distance between teeth and the long axis of each tooth, 18 anterior teeth were divided equally and randomly between group A and B. Samples in group A underwent cold light whitening, while samples in group B were treated with infiltration resin combined with cold light whitening. The color was measured before and after the treatment. Then, 6 teeth (the first subgroup) were randomly selected from the 18 anterior teeth after measurement for scanning electron microscopy (SEM) to observe the surface microstructure of the teeth. Then, another 6 teeth (the second subgroup) were selected from the remaining 12 teeth for the measurement of the color level and ΔE after being dyed with tea. Results After treatment, the color level changed significantly in group A and B (P < 0.05), ΔE in group A and B was 13.75, 14.98. There was no significant difference in the color level change between group B and group A, there was a significant difference in the ΔE between the two groups (t = -3.58, P < 0.05). SEM showed that the enamel surface was intact and that the enamel space was filled in group B. In group A, the enamel surface was reduced and uneven, and the characteristic badminton racquet shape of the enamel was not obvious. The color level was lower in both groups after staining, and these differences were significant (P < 0.05), ΔE in group A and B was 19.69, 18.95. There was no significant difference in the color level (t = 1.00, P > 0.05) and ΔE (t = 0.02, P > 0.05) between two groups. Conclusion Cold light whitening combined with infiltration resin is better for treating dental fluorosis than cold light whitening alone.