Transmission characteristics of liquid-core optical fiber used for 308 nm excimer laser instrument in vitiligo treatment were studied. The optical transmission under different laser power output and operation time of three different fibers were tested and compared. These fibers included UV extended liquid-core optical fiber, silica bundled fiber and ordinary liquid-core optical fiber. The transmissivity of UV extended liquid-core optical fiber was as high as 70%. The intensity distribution and beam homogenization via optical fiber were measured and analyzed. The beam homogenization via UV extended liquid-core optical fiber was less than ±4.5%. The results showed that transmission system based on liquid-core optical fiber for 308 nm UV laser has better transmissivity, homogenization and stability.