A method of double-side displacement-rotation flat-lapping with solid abrasives is proposed and a CNC machine tool is developed in this document. By analyzing the lapping principle and the structural characteristic of common solid abrasives flat-lapping method, the deficiencies of this method are indicated. The new method changes the motion pattern of workpiece in principle, the relative position between the workpiece and abrasive disks (lapping tools) are changed while the workpiece rotates. Therefore those deficiencies are made up radically, the lapping trace and velocity distribution of the relative motion between the workpiece and abrasive disks are more reasonable, the stress and wear states of isolating plate are improved as well. Finally, the driving moment and the speed of workpiece rotary are analyzed, and the relative velocity between the abrasive disks and workpiece is researched.