-The detritus from the decomposition of dead plant materials of Spartina with great biomass provides abundant food for the heterotrophs in estuarine and nearshore coastal waters. It is for this reason that the decomposition rates of S. anglica and S. alterniflora near the estuary of obsolete Huanghe River were studied. The changes in nutritive components during decomposition are also studied.Results showed that the decomposition rate of dead leaves of S. anglica on ultra-low marsh was about 90% for the first year. In the eighth month, it was 80% and 76 % respectively for S. anglica and S. alterniflora on low marsh. Protein content of the two species of Spartina increased in the course of decomposition, with a maximum increment of 100% or more. The energy value also increased, whereas cellulose content decreased markedly. The percentage content of ash and lipid varied significantly with zonal differences. -The detritus from the decomposition of dead plant materials of Spartina with great biomass provides abundant food for the heterotrophs in estuarine and nearshore coastal waters. It is for reason reason the the decomposition rates of S. anglica and S. alterniflora near the estuary of obsolete The changes in nutritive components during decomposition are also studied. Results showed that the decomposition rate of dead leaves of S. anglica on ultra-low marsh was about 90% for the first year. In the eighth month, it was 80% and 76% respectively for S. anglica and S. alterniflora on low marsh. Protein content of the two species of Spartina increased in the course of decomposition, with a maximum increment of 100% or more. The energy value also increased, while The content content of marked markedly. The percentage content of ash and lipid varied significantly with zonal differences.