The biogeochemical cycling of phosphorus(P) plays a pivotal role in the material-energy cycle of the biosphere, profoundly influencing the quality of water environments and the process of life succession. While traditional theories often consider the phosphorus cycle to be primarily sedimentary, with orthophosphate(P^+Ⅴ) as the primary driver, this neglects the presence of inorganic reduced phosphorus(IRP) forms such as phosphine(P^-Ⅲ), hypophosphite(P^+Ⅰ), and phosphite(P^+Ⅲ), which have lower valences than +Ⅴ. This oversight results in a significant knowledge gap in our understanding of P cycling in water bodies. The aim of this paper is to summarize our current understanding of IRP's sources, compositions, detection methods, spatial and temporal distribution, transport and transformation processes, as well as its bioavailability. It is expected to enrich and improve the lake phosphorus cycle theory to provide key information and a scientific basis for lake water environmental protection and management.