Abstract： The precision grinding principle of the spherical, aspherical and other large two revolving curved surface was analyzed. Besides, a novel method for grinding large rotating conicoid with two linear motion and a rotation was introduced. Moreover, an approach for a realtime detecting surface precision based on normal tracking was proposed, and the intelligently precisely grinding system was designed. The results show that with the application of this method, the grinding spindle rotation center line coincides with the normal line of the ground point on the quadratic rotated conicoid, thereby, improving the grinding accuracy and grinding efficiency.