Over the last 15 years, optical spectroscopy and imaging has been intensively studied to improve the detection and localization of early lung cancer. Autofluorescence bronchoscopy (AFB) is the most successfully developed technique and has significantly improved the detection sensitivity of early lung cancer. In this review, the optical principles behind white-light and autofluorescence bronchoscopy, as well as the role of AFB in the diagnosis of early lung cancer and the overall management of patients with early lung cancer are discussed. Other newest development such as Raman spectroscopy and simultaneous imaging and spectroscopy measurements are also highlighted.