In order to understand the nutrient characteristics of Meretrix meretrix and Mactra veneriformis, the general nutrients (crude protein, crude fat and crude ash), amino acids, as well as heavy metals (Cd, As, Cr, and Hg) in edible part of these two clams were investigated. The results showed that the crude protein content (58.24 g/100 g) and crude fat (5.93 g/100 g) in M. meretrix was similar to those in M. veneriformis (57.38 g/100 g, and 6.18 g/100 g). The polysaccharides content in M. meretrix is approximately three times as high as that in M. veneriformis. The crude ash contents in M. meretrix and M. veneriformis were 18.35 g/100 g and 25.39 g/100 g, respectively. In dry sample, the total amino acids content was up to 44.87 g/100 g in M. meretrix and 37.20 g/100 g in M. veneriformis. Meanwhile, contents of the essential amino acids and delicious amino acids in M. meretrix (18.39 g/100 g, 18.89 g/100 g) were higher than those in M. veneriformis (15.16 g/100 g, 15.58 g/100 g). The ratio of essential amino acids content to total amino acids was close in both buried clams and more than 40%. Among four heavy metals including Cd, As, Cr, and Hg, the Cd exhibited the highest content. The content of Cd was 5.40 mg/kg in M. meretrix and 6.3 mg/kg in M. veneriformis. It was found that the contents of Cr and Hg in M. meretrix and M. veneriformis were lower than the standard for the toxic substance in the non-environmental pollution aquatic products and other limit standards. Whereas, Cd and As contents in both estuarine buried clams were higher than the standard. Based on the PMTDI health risk evaluation model, the contents of heavy metals in both buried clams posed no health risk to humans. In conclusion, the results suggest that M. meretrix and M. veneriformis are both suitable for diet and delicious additives. Furthermore, M. meretrix is a more ideal protein source for humans given the composition and content of protein and amino acid.