The grinding and polishing machine is equipped with double discs, double control and double motors, suitable for pre-grinding, grinding and polishing operations of metallographic samples for PCB, FPC and IC products. It can realize stepless speed change and arbitrary switching of rotation direction. The left and right grinding and polishing discs can respectively obtain a rotation speed between 50-1500 rpm, and is equipped with a cooling device to cool the sample during pre-grinding to prevent damage to the metallographic structure due to overheating of the sample.