The optical imaging and detecting system is important for noninvasive detection of latent fingerprints, in which the power utilization and intensity distribution uniformity of illuminating and exciting light source have great influences on the revealing effect and the detection ratio. Using the ultraviolet (UV) transmitting liquid core fiber as the optical guiding and transmitting element for the illuminating and exciting light source, the transmission characteristics of liquid core fiber in UV range are experimentally investigated. The transmission efficiency of 266 nm laser in the liquid core fiber and the relationship between the transmission efficiency and the fiber curve radius are obtained, and the intensity distribution of output beam transmitted in the liquid core fiber is measured with the uniform intensity distribution. Using the liquid core fiber as the optical guiding and transmitting element for the light source in the fingerprints optical detecting system can improve the light utilization and realize the uniform illumination condition equired, and the results have application values.