Abstract: In this study, the Qilihai lagoon wetland reclamation area with the interior of the lagoon was selected as the research area.The reclamation area was divided into reclaimed for 32 years and 19 years, applying "space substitute for time", and combining on-site surveys and remote sensing interpretation. The spatial distribution characteristics of phosphorus occurring forms in the reclamation area and lagoon of different years was analyzed, and their ecological risks were evaluated. The results showed that the total phosphorus (TP) contents of sediment in the research area ranged from 255.59×10⁻⁶～74.90×10⁻⁶, inorganic phosphorus (IP) contents ranged from 210.90×10⁻⁶～428.92×10⁻⁶, organic phosphorus (OP) contents ranged from 10.78×10⁻⁶～56.06 ×10⁻⁶, iron-aluminum-bound phosphorus (Fe/Al-P) contents ranged from 19.89×10⁻⁶～86.22×10⁻⁶, and calcium-bound phosphorus (Ca-P) contents ranged from 140.03×10⁻⁶～276.55×10⁻⁶. TP, IP and Ca-P have similar spatial distribution characteristics, as shown the center of the lagoon> northwest of the reclamation area> northeast lagoon breeding area. Overall, the contents of phosphorus forms in the sediments of the lagoon center is generally higher than that in the reclamation area. After reclamation in wetlands, with the increase of breeding years, the content of various P forms increased to varying degrees. According to the characteristics of the single factor index data, the risk of phosphorus release increases with the increase of the reclamation period, and the risk of phosphorus release in the center of the lagoon is greater.