With the increase of aesthetic needs, tooth discoloration has gradually become the focus of attention. Tooth discoloration can be divided into endogenous coloring and exogenous coloring according to different specific reasons. The former is mainly caused by internal factors of teeth, such as pulp necrosis, tetracycline teeth and dental fluorosis, while the latter is often caused by food, smoking, and long-term stimulation of oral metabolites. The traditional tooth whitening technology has the problems of poor effect and damage to teeth. In recent years, with the development of oral whitening technology, the emergence of cold light whitening technology provides a new choice for tooth whitening. Cold light whitening technology has the technical advantages of outstanding therapeutic effect, convenient operation and high safety. In this regard, this study focuses on the research progress of the principle, efficacy, safety and remineralization treatment of cold light whitening technology in the treatment of discolored teeth, in order to provide reference for the clinical treatment of discolored teeth.