Objective To explore the effect of different tooth whitening techniques on tooth whitening effect in patients with tooth discoloration. Methods A total of 120 patients with tooth discoloration treated at the Department of Stomatology, the No.1 People's Hospital of Shizuishan from January 2023 to January 2024 were selected as the research subjects. According to the random number table method, they were divided into group A, group B and group C, with 40 patients in each group. Group A was treated with ultrasonic scaling, group B was treated with cold light whitening, and group C was treated with Opalescence whitening system. The tooth whitening effect, aesthetic satisfaction and adverse reaction rate were compared among the three groups. Results At 1 and 3 months after treatment, the L values of group B were higher than those of group A and group C, and those of group C were higher than those of group A (P<0.05). At 1 and 3 months after treatment, the a and b values of group B were lower than those of group A and group C, and those of group C were lower than those of group A (P<0.05). The aesthetic satisfaction of group B was higher than that of group A and group C, and that of group C was higher than that of group A (P<0.05). There was no signiffcant difference in the incidence of adverse reactions among the three groups (P>0.05). Conclusion In the treatment of tooth discoloration, the application of cold light whitening can effectively eliminate tooth discoloration and improve tooth brightness, with favorable safety, so as to greatly improve patients’ aesthetic satisfaction.