Phosphorus (P), a critical macronutrient for biological metabolic processes, plays an essential role in carbon (C) fixation and the decomposition of organic C within ecosystems. Its biogeochemical cycling is vital for C accumulation and release in peat wetland soils. This review synthesizes core literatures on P in peat soils, emphasizing the biogeochemical transformation and transport processes of P. Through a systematic analysis, we compare existing methods for determining P forms, highlighting their applicability and limitations. Our research further elucidates the distribution patterns of P within peat soil profiles, the mobilization of inorganic P, and the mineralization mechanisms of organic P, exploring the driving and controlling effects of physicochemical factors, plant influence, and microbial activity on the transformation of P forms in peat soils. The findings indicate that the biogeochemical cycling of P in peat wetland soils differs from that of common terrestrial soils, with its transformation and transport processes predominantly governed by the unique environmental characteristics of peat soils. Based on these insights, we propose two forward-looking directions for future research on P in peat soils: firstly, exploring the molecular biological mechanisms underlying the biogeochemical transformation and transport of P in peat soils to deepen our understanding of the microscale processes involved in the P cycle; secondly, investigating the impact mechanisms of changes in P forms and content on C and N accumulation and release, providing a new perspective on the interactions between elemental cycles in ecosystems. These research directions will lay a more solid theoretical foundation for the sustainable management of peat wetlands and enhance scientific understanding of the global C cycle.