Abstract: A TDA5005 total station with a large mount of reflector tapes was successful used in a large antenna's installation.The algorithm of distance incident angle was drawn.A new method for tape distance constant was developed.The offset correction for tape was also discussed.From this paper,it was found that the two methods,which were called surface free fitting and CAD surface fitting,were all the same for circular paraboloid.The effect of mechanical adjusting was proved by electronic testing.