The invention discloses a grinding device for an electronic product internal panel and a working method thereof. The grinding device comprises a transporting assembly, a grinding assembly, a moving assembly, a clamping assembly and a base; the grinding assembly is arranged over the transporting assembly; the clamping assembly is fixed to the lower end of the moving assembly; and a vertical supporting column is perpendicularly fixed to the upper surface of the base, a transverse supporting column is fixedly connected to the upper end of the vertical supporting column, and one end of the transverse supporting column is fixedly connected with the moving assembly. According to the grinding device for the electronic product internal panel and the working method thereof, safe transporting of a panel raw material is guaranteed, and the panel raw material can be ground fully; operation of all links of the device is controlled by a control panel, the device is easy and convenient to operate, the automatic degree is high, and use is convenient for people; the upper surface and the lower surface of the panel raw material can be ground simultaneously, and the grinding efficiency is high; and afirst motor drives a first pulley to rotate to drive the grinding assembly to move, the panel raw material does not need to be manually carried, time and labor are saved, and the working strength ofoperators is reduced.