The embodiment of the invention provides a mechanical polishing treatment method and a mechanical polishing treatment device and relates to the field of ultraprecision manufacturing. The method comprises the following steps of acquiring a first operation object for characterizing a polishing tool, a second operation object for characterizing a workpiece, a third operation object for characterizing a polishing solution and a fourth operation object for characterizing abrasive particles in the polishing solution; respectively acquiring physical property data of the first operation object, the second operation object, the third operation object and the fourth operation object; establishing a solid-liquid coupling model for characterizing a mechanical polishing process; on the basis of the solid-liquid coupling model, first motion parameters of the first operation object, second motion parameters of the second operation object and a preset simulation time slot, simulating and acquiring stress data of the second operation object and speed data of the fourth operation object; then obtaining first data and second data; analyzing and comparing the first data, and obtaining the first motion parameters and the second motion parameters, so as to improve the polishing efficiency in an actual mechanical polishing process.