Air duct structure and refrigerator

The invention relates to the technical field of refrigerators and provides an air duct structure and a refrigerator. The air duct structure comprises a first air return duct cover and a second air return duct cover, wherein the first air return duct cover is used for being arranged at the junction of a refrigerating chamber and a freezing chamber of the refrigerator and being connected with the refrigerating chamber and the freezing chamber, the second air return duct cover is arranged on a back plate of the refrigerator and is connected with the back plate, and the vertical length of the second air return duct cover is larger than that of the first air return duct cover, a first air return duct is arranged among the second air return duct cover, the first air return duct cover and a refrigerator container of the freezing chamber, a first air inlet and a first air outlet which communicate with the first air return duct are formed in the two ends of the first air return duct respectively, the first air inlet c