Objective To analyze the effect of cold light whitening in patients with tooth whitening. Methods A total of 70 patients who underwent tooth whitening treatment in Baoji Stomatological Hospital from January 2022 to December 2023 were selected as the study subjects. According to the random number table method, the patients were divided into control group and observation group, with 35 patients in each group. The control group was treated with bleaching treatment, and the observation group was treated with cold light whitening treatment. The tooth whitening effect, incidence of adverse reactions, Vita colorimetric value, enamel damage and treatment satisfaction were compared between the two groups. Results The total effective rate of tooth whitening in the observation group was 97.14%, which was higher than 80.00% in the control group (P <0.05). The incidence of adverse reactions in the observation group was 2.86%, which was lower than 20.00% in the control group (P <0.05). After treatment, the Vita colorimetric value of the observation group was lower than that of the control group (P <0.05). The incidence of enamel injury in the observation group was 2.86%, which was lower than 20.00% in the control group (P <0.05). The total satisfaction rate of the observation group was higher than that of the control group (P <0.05). Conclusion Compared with bleaching whitening method, cold light whitening method can not only improve the whitening effect of teeth, reduce the incidence of adverse reactions and enamel damage rate, but also improve patient satisfaction, which is worthy of clinical application.