Abstract: According to the data of classification survey on shellfish-culture areas of Lianjiang southeast sea area in April, June and August 2009, the concentrations of the harmful substances (such as Cu, Pb, Cd, Hg, As, petroleum, DDT, PCBs, coliforms, DSP and PSP) of shellfish (Haliotis nigra, Mytilus galloprovincialis, Saccostrea cucullata, Crassostrea gigas, Sinonovacula constricta and Ruditapesphilippin Adams) were analyzed. The results showed that the wet-weight concentration range of Cu, Pb, Cd, Hg, As, petroleum, DDT, PCBs and coliforms of four shellfishes were (0.87~84.1) mg?kg-1, (0.018~0.42) mg?kg-1, (0.011~1.0) mg?kg-1, (0.003~0.05) mg?kg-1, (0.082~0.89) mg?kg-1, (2.56~61.1) mg?kg-1, (0.11~523)×10-3 mg?kg-1, (0.023~337)×10-3 mg?kg-1, (15~230) MPN?100 g-1, (0.7~1300) CFU?g-1, separately. The average wet-weight concentrations were 12.7 mg?kg-1，0.17 mg?kg-1，0.16 mg?kg-1，0.007 mg?kg-1，0.30 mg?kg-1，17.5 mg?kg-1，77×10-3 mg?kg-1，23×10-3 mg?kg-1，37MPN.100g-1. The concentrations of DSP and PSP were not detected. Based on the limit standard for the toxic substance in the aquatic products on pollution-free food (NY/T 5073-2006) and the standard for pollution-free aquatic products safety on quality and safety agricultural products (GB 18406.4-2001), the quality and safety of six shellfishes was evaluated by single factor standard index method and Nemerrow environmental quality comprehensive evaluation index method. The result of assessment indicated that the quality grades of Haliotis nigra, Mytilus galloprovincialis, Saccostrea cucullata, Crassostrea gigas and Ruditapesphilippin Adams ranged from grade 2 to 4, averaging Grade 3, and the shellfish quality was at a relatively good level. Whereas quality grades of Sinonovacula constricta ranged from grade 2 to 6, averaging Grade of 6, and the shellfish quality was at a relatively bad level.