Abstract: A method to design coupling lens of fiber lighting based on the free-form surface is proposed. Through non-imaging optics design, based on the Etendue and the Snell's law, the iterative optimization of free-form surface is conducted, and the low-loss coupling between light source and optical fiber is realized. Simulation results show that using the LED chip as the light source, this lens can improve the flux transmission efficiency above 89% and has good applications and development prospects.