Abstract: Investigation and determination was carried out on chlorophyll a, primary productivity, ecologic efficiency, organic carbon content in plankton and cultured shellfish, and the weight ratio of whole shellfish and fresh tissue, filtering ratio of cultured shellfish and wild filtering animal, existence of filtering animal in tidal area, under tidal area and hanging culture area Nutrition dynamic model and coastal energy transfer model were used to estimate the shellfish ecological capacity. The shellfish culture capacity was estimated by excluding the biomass of wild filtering animal Fang Jian-guang's model was also used to estimate shellfish culture capacity. Statistic analysis was made to estimate optimal culture area for each shellfish species. The shellfish culture capacity of Zhaoan Bay estimated through the three models were 58 469 t, 288 260104 ind, 60275 t,297 167104 ind and 61 532 t, 30 336104 ind, respectively, averaged 60 092 t, 296 263104 ind. The shellfish optimal culture area in total was 2 755 hm2, among which Sinonovacula constricta 25 hm2, oyster 1 560 hm2, Perna viridis 215 hm2, Ruditapes philipinarum 120 hm2, Tegillarca granosa 30 hm2, Musculista senhausia 95 hm2, Paratapes undulata 710 hm2.