Objective To investigate the variation in heavy metal elements content in Mizuhopecten yessoensis and Anadara broughtonii from the Dalian Region. Methods Samples of Mizuhopecten yessoensis and Anadara broughtonii were collected monthly over the course of a year in Dalian. The content of heavy metal elements, including Pb, Cd, Cr, and Cu, were determined using inductively coupled plasma mass spectrometry. The study examined the monthly trends in the accumulation of these elements in the 2 types of shellfish. The single-factor pollution index method and the target hazard quotient method were used to evaluate the consumption risk and potential health risks to humans from consuming shellfish products with accumulated heavy metals. Results The Cd content in Mizuhopecten yessoensis peaked in March, with the highest detected value reaching 4.50 mg/kg, exceeding the national food safety standard limit. The Cu content in Mizuhopecten yessoensi was significantly higher in March, April, and October compared to other months, but all annual detection values were below the limit. In Anadara broughtonii, the Cd content peaked in March and April, with the highest detected value being 1.92 mg/kg, but no significant variation pattern was observed in other months, and all annual detection values were below the limit. The content of other heavy metal elements did not show significant variation patterns over time or seasons. Conclusion The heavy metal content in Mizuhopecten yessoensis shows the most significant monthly variation. For Cd, Mizuhopecten yessoensis are contaminated in March, April, and May, posing health risks if consumed. Anadara broughtonii remaines within safe consumption levels throughout the year, with lower health risks.