To investigate the effect of salinity on silicon, carbon, and nitrogen values during decomposition of wetland litter, the changing dynamics of silicon, carbon, and nitrogen in Spartina alterniflora stems and leaves under different salinities (0, 5, 15, and 30) were analyzed in the laboratory. The results showed that the percentage weight loss and decomposition rate of litter decreased with increasing salinity. The silicon release concentrations of litter increased with higher salinity, and were significantly greater in the high salinity treatment (30) than in the freshwater(0) and low salinity(5) treatments (P < 0.05). In contrast, the biogenic silica (BSi) residual contents demonstrated an opposite trend during the terminal decomposition. The carbon contents released from the stem were not significantly different between the different salinity treatments, but the leaf were lower in the freshwater treatment than in the other treatments (P < 0.05). In the higher salinity treatments, the stem litter had higher NH₄⁺-N release, with NO₃^--N contents shown to be the opposite. Salinity impact studies on litter decomposition and element release provides reference information for decomposition responses of tidal wetland litter to saltwater intrusion and is the basis for further research on biogeochemical cycles of biogenic elements in wetlands.