Lithium iron phosphate (LFP) batteries, boasting significant advantages in cost-effectiveness, safety, and longevity, are extensively utilized as the core components for electric vehicles. However, with the increasing end-of-life of LFP batteries, the recycling of these spent batteries has become a crucial and urgent matter. Given the relatively short process and high-value-added recycled products, the direct regeneration of cathode materials from spent LFP batteries has become a highly preferred approach. This paper provides a comprehensive review of the research status and technical challenges of direct regeneration technologies (i.e., solid-phase sintering, hydrothermal repair and electrochemical repair technology) applicable to spent LFP cathode materials. The failure mechanisms of LFP, as well as the detailed processes and recent advancements in recycling pretreatment are elaborated and summarized. Additionally, this paper extends to introduce the research advancements in innovative upgrading regeneration of cathode materials. Finally, a comparative analysis of the three direct regeneration strategies is conducted, emphasizing their respective advantages, limitations, and target application fields. It is anticipated to establish a comprehensive reference framework for the efficient regeneration and reuse of cathode materials from spent LFP batteries, thus promoting the green and sustainable development of the new energy vehicle industry.