The invention discloses a double-sided grinding method of a sapphire ball cover. The method includes the following steps: grinding the sapphire ball cover simultaneously by using two hemispherical grinding wheels; clamping a sapphire crystal ingot with a ground end surface on symmetrical annular fixtures; fixing the outer circular surface of the sapphire crystal ingot; grinding a grinding plane annular region to be adhered to a safety holding ring; grinding the inner spherical surface of the sapphire by using a convex hemispherical grinding wheel; grinding the outer spherical surface of the sapphire ball cover by using an concave hemispherical grinding wheel; keeping a workpiece fixed; mounting the convex semi-spherical grinding wheel and the concave semi-spherical grinding wheel on upperand lower main shafts of a vertical grinding machine, wherein the upper and lower main shafts are coaxial, the two main shafts rotate in the same direction or in opposite directions, and can be fed vertically; grinding the sapphire ball cover into the final stage; reducing the feed rate of the grinding; stopping the grinding of the outer spherical surface of the sapphire antenna cover; grinding the inner spherical surface of the sapphire by the convex semi-spherical grinding wheel; after the grinding of the inner spherical surface is finished, withdrawing and stopping the convex semi-sphericalgrinding wheel; and grinding the outer spherical surface of the sapphire ball cover by the concave semi-spherical grinding wheel until the sapphire ball cover is processed.