The invention provides a solid material mixing device which comprises a mixing room, a first feed channel and a second feed channel, wherein the first feed channel and the second feed channel are both located at the top of the mixing room and are vertically and obliquely arranged relative to the cross section of the mixing room respectively; multiple spaced first bulges and second bulges are arranged on the opposite two sides of the inner wall of the mixing room respectively; the top sides of the first bulges and second bulges are all obliquely arranged relative to the inner wall of the mixing room; clearances are reserved between free ends of opposite first bulges and second bulges and all tilt toward the bottom end of the mixing room; the extension surface of the top side surface of the first bulge extending along the tilting direction is crossed with the second bulge adjacent to the first bulge; and the extension surface of the top side surface of the second bulge extending along the tilting direction is crossed with the first bulge adjacent to the second bulge. The solid material mixing device realizes relatively sufficient mixing of solid materials without a moving component or the drive of external forces, and thus use of energy is reduced.