The invention discloses a 3D (Three-dimensional) bent glass hot bending machine, which comprises a feeding and replacing vacuum chamber, a full-sealed furnace cavity, a blanking and replacing vacuum chamber and a graphite jig. According to the hot bending furnace cavity with a full-sealed structure, high-purity nitrogen is fed into the furnace cavity, the vacuum chambers are respectively arrangedon a feed inlet and a discharge hole of the furnace cavity, each vacuum chamber is provided with two sealed gates which respectively lead to the furnace cavity and the outside world, the sealed gatesserve as channels for a mould to enter the vacuum chambers and enter the furnace cavity from the vacuum chambers, and before the mould enters and exits the furnace cavity, protected gas and air replacement is accomplished in the vacuum chambers, so that outside air is prevented from entering the mold and the furnace cavity. The oxygen content in the hot bending furnace cavity and a mould cavity can be greatly reduced, the service lifes of the mould and key high-temperature parts of the hot bending machine are prolonged, the product quality is improved, and the manufacturing cost is reduced.