The invention discloses a high-temperature chain grate and rotary hearth furnace united direct reduction system. The system comprises a high-temperature chain grate, a loading machine, a rotary hearth furnace and a flue, wherein the rotary hearth furnace is used for producing a reducing atmosphere for reducing a material; the high-temperature chain grate and the rotary hearth furnace are connected with the flue through the loading machine; the high-temperature chain grate comprises an inlet, a drying section, a preheating section and a high-temperature section; the rotary hearth furnace comprises a furnace roof, a furnace wall and a chassis and is divided into a loading area, a medium-temperature reduction area, a high-temperature reduction area and an unloading area; flue gas generated in the rotary hearth furnace directly enters the high-temperature section of the high-temperature chain grate through the flue. In comparison with the prior art, the high-temperature chain grate and rotary hearth furnace united direct reduction system disclosed by the invention is provided with the high-temperature chain grate and the rotary hearth furnace which are arranged together; the high-temperature flue gas of the rotary hearth furnace directly enters the high-temperature section of the high-temperature chain grate; a high-temperature material discharged from the high-temperature chain grate is directly distributed inside the rotary hearth furnace through the loading machine and has a quick reaction, so the treatment capability of the rotary hearth furnace is greatly improved, and meanwhile the equipment investment of a flue gas afterheat recycling device of the rotary hearth furnace is reduced.