Based on the support of new developments in optical imaging, noninvasive, in situ, dynamic, real-time clinical skin diagnosis is realized. A new branch of the medical imaging and skin imaging has been developed as a new technical discipline for the past decade. This review focuses on the current optical imaging techniques that have been used in clinical diagnosis, including dermoscopy, confocal imaging, multiphoton imaging, optical coherence tomography and photoacoustic imaging. These five optical clinical diagnosis methods can supply a doctor with detailed and precise information of the targeted suspicious skin area, which provide objective evaluation. These new developments in skin imaging, compensate to the advances of skin histopathology research, will promote the fast development of modern dermatology.