Objective To analyze the application effect of resin infiltration combined with Beyond cold light whitening instrument in the aesthetic restoration of dental fluorosis. Methods A total of 98 patients with dental fluorosis admitted to our hospital from February 2022 to February 2024 were selected as the research subjects. According to the random number table method, they were divided into the control group and the observation group, with 49 patients in each group. The control group was treated with the Beyond cold light whitening instrument, and the observation group was treated with resin infiltration on the basis of the control group. The tooth surface lesion area, color scale improvement value, tooth sensitivity score, aesthetic restoration satisfaction and plaque index were compared between the two groups. Results The tooth surface lesion areas in the observation group at 1 week and 1 month after operation were (19.15±4.09)mm2 and (9.53±2.40)mm2 respectively, which were lower than (23.02±4.62)mm2 and (12.61±2.95)mm2 in the control group (P <0.05). The color scale improvement values in the observation group at 1 week and 1 month after operation were higher than those in the control group, and the plaque index scores were lower than those in the control group (P <0.05). The tooth sensitivity score in the observation group at 1 month after operation was lower than that in the control group, and the scores of aesthetic restoration satisfaction (appearance, tooth integrity, color matching degree) were higher than those in the control group (P <0.05). Conclusion In the aesthetic restoration of dental fluorosis, the combination of resin infiltration and Beyond cold light whitening instrument can effectively reduce the tooth surface lesion area, improve the appearance of the affected teeth, reduce the tooth sensitivity, and enhance the aesthetic restoration satisfaction.