Iron ore is an important raw material for manufacturing steel, while the grade of domestic iron ore is relatively low in China, thus it is difficult to concentrate. The low-grade iron ore with a total iron content of only 33.51% is innovatively upgraded by the magnetic-gravity combined beneficiation method. The effects of three key operating parameters of magnetic induction, grinding concentration, and centrifuge speed on magnetic-gravity combined beneficiation are investigated. These results show that the magnetic-gravity combined beneficiation method significantly improves the iron grade of the concentrates at high recovery. The feasibility is further confirmed through continuous expansion semi-industrial tests with the optimized parameters. The grade of the iron ore concentrate is increased from 33.51% to 63.58% with an iron recovery of 71.01% and a productivity of 37.43%. It is thus concluded that the magnetic-gravity combined beneficiation method has provided a technical reference for the recovery of iron resources from low-grade ores.