In order to solve the lacking of calibration means when working in the field， the Beidou Navigation Satellite System（BDS） is used to evaluate telescopes' astronomy and axis orientation precision， which survey the Medium And High Earth Orbit Objects（MHEO）. This research is dedicated to deduce the principle of astronomy and axis orientation， and testify the feasibility of evaluating the electro-optical telescope's accuracy with BDS by analysising the satellites' coverage， orbit pricision and brightness， which has big diameter. Firstly， we interpolate the regular BDS precise ephemeris by Lagrange polynomial， whose data interval is 5 minutes. With coordinate conversion， we get the apparent ascension and apparent declination in the agreement celestial coordinate system， azimuth and pitch in the station coordinate system， which are the true value for astronomy and axis orientation precision evaluation. A MHEO telescope's astronomy orientation precision is superior to 2″ and axis orientation precision is superior to 7″ by this method.