Using the liquid crystal spatial light modulator and Shack-Hartmann wave front sensor as the core components, an adaptive optics (AO) system for retinal imaging in vivo is constructed. Based on the modulation transfer function, quantitative analysis of the effects of the intraocular stray light on retinal imaging is carried out. The result demonstrates that the ocular stray light degrades the quality of the retinal images. According to the change characteristic of the polarization state of intraocular stray light. The fundus is illuminated by the polarized light. With the help of trial lens and sighting target with focal length of 1 m, the light source can be precisely focused on the capillary layer of the retina. Adopting the above mentioned methods, the effect of the ocular stray light is inhibited and the quality of retinal images is improved. Four volunteers participates in the experiments. The clear capillary images are obtained.