Sodium metal has the advantages of abundant sources,low cost and uniform distribution,so sodium-ion batteries are considered to be one of the most promising large-scale energy storage systems.The cathode material in sodium-ion batteriesis a critical factor affecting both the electrochemical performance and production cost of the battery.Layered transition metal oxides have attracted significant attention because of their high energy density,simple synthesis method and environmental friendliness. This paper provides a comprehensive summary and review of the research on layered cathode materials from the perspective of their composition structure,phase transition mechanism,charge compensation mechanism,and modification strategies,which reveal the key factors limiting the improvement of the electrochemical performance of layered cathode materials,analyzing the effective means to inhibit phase transition process and the rational design to enhance the reversibility of anion redox reaction.Furthermore, this paper offers an outlook on future development trend.