Ruditapes philippinarum is abundant around the seagrass meadow in Chudao, Sanggou Bay. To determine the interactions between R. philippinarum and Zostera marina L., the amount of R. philippinarum was evaluated in the seagrass meadow at Chudao from May to July, 2016. The feeding and metabolic physiology of R. philippinarum were determined based on an individual experiment with flowing water from the field. The interactions between R. philippinarum and Z. marina were investigated in an enclosure experiment in the field. The results showed that the biomass of R. philippinarum was (572.00±20.23) ind./m2, which included 9.01% large (shell length 3.50~4.10 cm), 43.60% medium (shell length 3.00~3.50 cm), and 47.38% small (shell length 2.00~3.00 cm) clams. The ammonia nitrogen excretion, oxygen consumption, clearance rate, and feeding rate were (0.44±0.15) to (1.40± 0.35) μmol/(ind.·h), (0.21±0.02) to (0.33±0.08) mg/(ind.·h), (0.69±0.38) to (0.83±0.66) L/(ind.·h), and (2.57±0.41) to (3.41±0.68) mg/(ind.·h), respectively. These parameters all increased with increasing body weight of the clams. There were four groups (R. philippinarum, Z. marina, Z. marina+R. philippinarum, and control) with three replicates each in the enclosure experiment, which was run for 4 h. The results revealed significant differences in dissolved oxygen concentration among the R. philippinarum, Z. marina+R. philippinarum, and Z. marina groups (P<0.05). The ammonia nitrogen concentration in the R. philippinarum group was significantly higher than that in the other three groups (P<0.05). Total particles in the R. philippinarum and Z. marina+R. philippinarum groups were significantly lower than those in the control (P<0.05), while no significant difference was found between the Z. marina group and the control (P>0.05). The area of R. philippinarum is about 0.5 km2 around Chudao in Sanggou Bay, approximately filter 46 t of suspended particulates and provide 0.4 t of ammonia nitrogen to the Z. marina meadow by the clam each day. The present findings provides basic data for further revealing the ecological roles of R. philippinarum in Z. marina meadow areas.