The invention relates to an open mill roller rubber block plate device. The open mill roller rubber block plate device comprises a rack and a first rubber block plate, a second rubber block plate, a third rubber block plate and a fourth rubber block plate which form a feeding port, wherein the third rubber block plate and the fourth rubber block plate are fixedly arranged on the rack radially, the first rubber block plate and the second rubber block plate are arranged axially, the two ends of the upper portion of the first rubber block plate and the two ends of the upper portion of the second rubber block plate are fixedly provided with rotating shafts respectively, and the rotating shafts are arranged on the rack in a hinged mode; the two sides of the lower portions of the first rubber block plate and the two sides of the lower portions of the second rubber block plate are provided with locking devices respectively, and each locking device comprises a machine base, an air cylinder, a first locking wedge block and a second wedge block, wherein the machine base is fixedly arranged on the rack, the air cylinder is fixedly arranged on the machine base, the first locking wedge blocks are fixedly arranged at the lower portions of the first rubber block plate and the second rubber block plate, the inclined plane of the first locking wedge block is opposite to the inclined plane of the second locking wedge block, and the other plane of the second locking wedge block is connected with a piston rod of the air cylinder. According to the open mill roller rubber block plate device, an open mill is of a fully-enclosed structure, and therefore rubber materials inside are kept in.