Magnesium-ion batteries are considered the next-generation promising large-scale energy storage devices owing to the low-cost and nondendritic features of metallic Mg anode. Nevertheless, such strong electrostatic interaction between bivalent Mg 2+ and crystalline cathode materials will lead to low capacity and poor diffusion kinetics, which seriously hinders the further development of magnesium-ion batteries. Herein, amorphization and anion-rich strategies are employed to prepare well-designed cathode materials with MoS 3 anchored on hollow carbon nanospheres (a-MoS 3 /HCS). The amorphous MoS 3 provides unrestricted 3D diffusion access and effectively boosts the Mg 2+ diffusion kinetics, while the anion-rich feature of MoS 3 offers rich active sites for Mg 2+ storage and finally contributes to a high discharge capacity driven by the anionic redox mechanism. Moreover, the effective modification of hollow carbon nanospheres buffers the volumetric changes of MoS 3 and improves the electron transfer efficiency. Owing to the abovementioned multiple advantages, a-MoS 3 /HCS exhibits an ultrahigh discharge capacity (489.2 mAh g −1 at 50 mA g −1 ) and high cyclic performance (200.1 mAh g −1 at 2 A g −1 for 300 cycles), distinctly superior to those of crystalline 1T/2H-MoS 2 /HCS and 2H-MoS 2 /HCS and surpassing almost all of the molybdenum sulfide-based cathodes. Furthermore, the high-performance a-MoS 3 /HCS-based pouch cell with the ability to drive various mini-type devices confirms the potential application values. The excellent magnesium storage properties of a-MoS 3 /HCS are further verified by the related kinetics analysis, DFT theoretical calculation, and reversible electrochemical reactions. The amorphous and redox-rich tactics of a-MoS 3 /HCS provide an innovative pathway to explore high-efficiency cathode materials for various multivalent-ion batteries.