Grinding roller device for coal grinding and coal grinding method

The embodiment of the invention provides a grinding roller device for coal grinding and a coal grinding method. The grinding roller device for coal grinding comprises a shell, a coal inlet pipe, an air blowing piece, a grinding assembly and a sorting assembly. The grinding assembly and the sorting assembly are both arranged in the shell, and the sorting assembly is arranged above the grinding assembly; the sorting assembly comprises a guide hopper located in the shell, a pulverized coal separation structure and a discharge hopper, the outer edge of the pulverized coal separation structure is connected with the guide hopper, the guide hopper and the shell form a first channel, the pulverized coal separation structure is provided with a second channel, the discharge hopper and the coal inlet pipe form a third channel, and the guide hopper and the coal inlet pipe form a fourth channel. The grinding assembly, the first channel, the second channel and the third channel communicate in sequence to form a powder disc