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, 288 260×10⁴ ind, 60275 t, 297 167×10⁴ ind and 61 532 t, 30 336×10⁴ ind, respectively, averaged 60 092 t, 296 263×10⁴ 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.