Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) is a large aperture and wide field telescope whose image quality requirement at Xinglong station is 80% light energy within 2 arcsecond. In fact, the designed image quality of the central field of view is diffraction limited under optical wavelength. Due to the 60m long light path and

poor natural seeing, dome seeing and other errors, the image quality is averaged about 0.5arcsecond to 1 arcsecond. We consider deploying a low-order adaptive optics system on LAMOST to improve seeing conditions and the corresponding image quality. Based on the sounding balloon results on Xinglong Station, we make the numerical simulation of the AO performance and get Fried parameter, the final point spread function (PSF) characteristics of LAMOST including Strehl ratio, full width at half- maximum (FWHM), and the residual variance.