The invention discloses a copper oxide reduction device and a method. The copper oxide reduction device comprises a box-type electric furnace, a quartz tube, internal nut sealing pieces and external nut sealing pieces which are matched with the internal nut sealing pieces to use. Two ends of the quartz tube are sealed due to the fact that the internal nut sealing pieces are tightly matched with the external nut sealing pieces. A groove matched with the quartz tube is formed in the box-type electric furnace. An air inlet is formed in the external nut sealing piece of one end of the quartz tube. An air outlet is formed in the external nut sealing piece of the other end of the quartz tube. The copper oxide reduction device and the method can solve the problems that when granulated copper is reduced in the existing elemental analyzer, the elemental analyzer is occupied, and normal use of the elemental analyzer is influenced.