Abstract: By simulating amplitude and phase fluctuations induced by atmospheric turbulence, signal fading for coupling space light into single mode fiber is studied in wavefront tip-tilt corrected system. Tracking algorithm of CCD image is studied. Simulation results show that when the ratio of the receiving aperture to the Fried’s parameter is large, the performance of tip-tilt corrected system using centroid tracking algorithm is very poor and the signal fading depth is very large. A gaussian template matching tracking algorithm is proposed and by using this algorithm, the signal fading depth can be reduced greatly when the ratio of the receiving aperture to the Fried’s parameter is large, and that the disadvantage of the performance of large aperture may be inferior to that of small aperture ca