Direct imaging of exoplanets and candidates is a hot topic in international astronomy research today, and the large-scale census of potential exoplanet candidates will be an urgent need for astronomy in the next decade. The ROBO-AO Rayleigh laser beacon adaptive optical system deployed on 2 m class telescopes is essential for sensitive and rapid characterization of the exoplanet candidates, but the focus anisoplanatism effect caused by the height of Rayleigh beacons is an important factor affecting its planetary detection capabilities. An exoplanet high-contrast imaging system for the 61 units sodium beacon adaptive optics system of the 1.8 m telescope was constructed. It would provide high-contrast imaging of exoplanets in the near-infrared wavelength. By simulating the sodium beacon AO high-contrast imaging process, the high-contrast imaging performance of the exoplanets of the sodium beacon AO system was better than that of ROBO-AO in theory, and within two hours of exposure time, direct imaging of planets with a parent star light flux ratio of 4×10^-7 could be achieved, while under the same environment, the direct imaging capability of ROBO-AO exoplanets is 1×10^-6, where the angular distance between the planet and the star is 1''''.