Abstract: In order to elucidate the role of bottomcultured clams in the coastal nutrient cycle, the seasonal filtration, ingestion and biodeposition rates were in situ measured and carbon (C), nitrogen (N) and phosphorus (P) budgets of Ruditapes philippinarum among four seasons were modeled. The results showed that the scope for growth of R. philippinarum in carbon (SFG_C), nitrogen (SFG_N), and phosphorus (SFG_P) all varied significantly among seasons, with the highest values in spring. Meanwhile, SFG_C was negative in summer, SFG_N and SFG_P were always positive throughout the year. The seasonal variations of SFG_C, SFG_N and SFG_P were -3.94-49.82 mg C·ind^-1·d^-1, 0.72-9.49 mg N·ind^-1·d^-1, and 0.15-3.06 mg P·ind^-1·d^-1, respectively. The net growth efficiencies in carbon (K_C2), nitrogen (K_N2), and phosphorus (K_P2) also showed a distinct seasonal pattern among seasons, and ranked as K_P2> K_N2> K_C2. The C, N, and P budgets illustrated that the R. philippinarum population relatively used more N and P than C for growth and efficiently transferred the pelagic primary production to a higher trophic level. The current study suggested that R. philippinarum bottomcultured at large scale might play a dominant role in the nutrient cycle of the coastal ecosystem and should be considered as an important ecological component in coastal areas.