The invention discloses a corn combine harvester. The harvester consists of a rack, a header, a gap bridge, a threshing device and a grading device. The header is connected to a threshing chamber through the gap bridge. The threshing chamber is fixed on the rack. The gap bridge is hinge jointed to the rack through a bearing block of a driving shaft. The threshing device consists of a threshing chamber, and a threshing cylinder installed in the threshing chamber. The threshing chamber consists of an upper cover and a concave grate. The grading device consists of a grading sieve. The header is a header for harvesting wheat. The gap bridge is a gap bridge for harvesting wheat. The concave grate is a grid concave grate. The grading sieve is a fish scale grading sieve. The corn combine harvester can efficiently reduce the purchase cost of corn harvesters, increase the usage frequency of corn combine harvesters, and reduce the production cost of users.