In order to obtain the high resolution human retinal images in vivo, an adaptive optical (AO) system for retinal imaging was designed to correct the dynamic human eye wavefront aberrations, especially high order ones.On the basis of an open-loop and two-wavelength mode, the system adopted a Shark-Hartmann wavefront sensor (SHWS) and a liquid crystal spatial light modulator to detect and correct the wavefront aberrations respectively and used a 790 nm near infrared luminescent diode and a 570 nm visible laser for the wavefront detection and retinal imaging.Furthermove,a reflective off-axis system was adopted to enhance the energy-utilizing rate and to avoid the chromatic aberrations and stray light.The optical system was simulated and analyzed with ZEMAX and results show that the optical system can achieve the diffractive limit, and MTF@30 lp/mm is 0.4(4 μm at retina)，MTF@50 lp/mm is 0.16(2.5 μm at retina).Compared with the close-loop refractive AO system,the system has doubled the energy-utilizing rate at least,and shows its some merits in high energy-utilizing rate,low stray light and little disturbing effect caused by chromatic aberrations.