Abstract: The sticking point of spatial light-single-mode fiber is to find the best position in the transverse plane of fiber precisely. Based on optical fiber migration's influence on the spatial light-single-mode fiber coupling efficiency, an auto-coupling system was proposed, which mainly consisted of two-dimensional piezoceramics, driver, controller, photoelectric detector which was a closed loop control system and coupling lens. The automatic alignment coupling of the spatial light-fiber was realized by combining with simulated annealing algorithm. The coupling efficiency for free-space laser coupling into the fibers and simulated annealing algorithm were analyzed theoretically. Analysis results of experiment show that the method can make the system search the best position automatically based on the power of the light which is coupled into the single-mode fiber. The optimal coupling efficiency is about 51.4%, which can be obtained in short times by the system and it is improved by 6.5% compared with no automatic alignment before. The scheme is practical and it is of great significance for the study of the automatic coupling of spatial light-single-mode fiber.