Autofluorescence has great advantage on detecting premalignant lesions and early cancers which are not detectable by conventional white light endoscopy (WLE). In this review, the recent advances in autofluorescence for diagnosis of precancerous lesions and early cancers are presented. Varieties of endogenous fluorophores in biological tissues, the potential mechanisms of the autofluorescence differences between normal and abnormal tissues, the selection of light source and optimal excitation wavelengths, and effective algorithms for processing autofluorescence data are highlighted. Finally, the shortages and improvement directions of autofluorescence technique for the diagnosis of precancerous lesions and early cancers are briefly discussed.