Sodium-ion batteries (SIBs) have aroused tremendous attention as the large-scale energy storage devices and low-speed electric vehicle power sources owing to the low-cost and abundant sodium reserves. However, the larger size and heavier mass of Na+ ion than those of Li+ ion often cause the sluggish reaction kinetics, hindering the practical applications of SIBs. Since cathodes determine the cost and electrochemical performance of batteries to a great extent, developing high-performance cathode materials is of great significance to the development of SIBs. Among the reported cathode candidates, layered oxide materials hold great potential due to their high capacity and facile synthesis process. Nonetheless, the layered oxides still face some challenges such as low capacity retention and poor air stability. In recent years, exploring appropriate methods to strengthen the structural stability and further enhance the energy density of layered oxides has becoming an emerging research hotspot. In this regard, various strategies have been proposed, such as the manipulation of element composition and relative content, modulation of microstructure and surface/interface. In this review, we summarize the up-to-date research progress on the typical modification methods for layered oxide cathodes, including component design, structure design, and surface design. Moreover, the challenging issues and possible remedies in the future are emphatically discussed. We believe that this review will shed light on the development of advanced layered oxide cathode materials for sodium-ion batteries.