The invention discloses a rotary type variable frequency pulverized coal deep separation and uniform distribution device and method for a medium speed coal mill. The rotary type variable frequency pulverized coal deep separation and uniform distribution device is characterized in that a separating and mixing conical section sleeves the side surface of a coal dropping pipe in a noncontact manner; a residual rotation elimination and uniform distribution grid and a plurality of axial flow blades are arranged in the separating and mixing conical section in sequence from top to bottom; a finished pulverized coal airflow outlet of a separator communicates with the bottom opening of the separating and mixing conical section; the top opening of the separating and mixing conical section communicates with a pulverized coal pipe through a pulverized coal pipe inlet conical section; an annular coarse pulverized coal return passage partition is positioned in the separating and mixing conical section and positioned between the separating and mixing conical section and the axial flow blades; the annular coarse pulverized coal return passage partition and the inner wall of the separating and mixing conical section form an annular coarse pulverized coal return passage; the top opening of the annular coarse pulverized coal return passage is positioned above the axial flow blades; and the bottom opening of the annular coarse pulverized coal return passage is positioned below the axial flow blades. According to the rotary type variable frequency pulverized coal deep separation and uniform distribution device and method for the medium speed coal mill, the problem of a greater distribution deviation in the pulverized coal quantity of the pulverized coal pipe is fundamentally solved, the deep separation of pulverized coal is realized, and the quality of pulverized coal is higher.