The drug fluorescence optical imaging system for diagnosis and localization of early nasopharyngeal carcinoma is theoretically analyzed,and the design approach of optical system and scheme is also presented in detail.The design of optical imaging system mainly includas the coupled technique with high efficiency between light source and optical fiber,and the directed coupled technique of two coaxial optical beam from different optical fiber without contact,as well as the technique for better clearness and contrast of displayed image of the optical imaging system.