Objective To explore the effect of cold light whitening system on tooth whitening and whitening satisfaction in patients with discolored teeth. Methods A total of 80 patients with discolored teeth treated in Yangzhou Stomatological Hospital from June 2023 to October 2024 were selected as the research subjects, and they were divided into the control group and the observation group by the random number table method, with 40 patients in each group. The control group was treated with tooth bleaching agent, and the observation group was treated with cold light whitening system. The tooth whitening, dental sensitivity, gingival inffammation, whitening satisfaction and external cervical resorption were compared between the two groups. Results The ΔE* values of the observation group at 2 weeks, 3 months, 6 months and 12 months after treatment were higher than those of the control group (P<0.05). There were no statistically signiffcant differences in dental sensitivity and gingival inffammation between the two groups (P>0.05). The whitening satisfaction of the observation group was better than that of the control group (P<0.05). There was no statistically signiffcant difference in the incidence of external cervical resorption between the two groups (P>0.05). Conclusion Cold light whitening system can improve the whitening effect and satisfaction for patients with discolored teeth, which is a safe and effective clinical scheme for aesthetic treatment of discolored teeth.