Frozen-cooked product is a common product form of Ruditapes philippinarum, with heating shelwith being a key processing technique.The basic principle of heating shelling relies on thermal contraction of the adductor muscle to separate the meat from the shell. Temperature is one of the crucial factors significantly affecting the protein in the adductor muscles of R. philippinarum. To inivestigate the correlation between adductor muscles decalcification and thermal denaturation of myofibrillar proteins in R. philippinarum following heat treatment, the thermal denaturation behavior of adductor muscle protein was initially investigated using a differential scanning calorimeter (DSC). Subsequently, the impact of heating on the microstructure of adductor muscles was observed using optical and electron microscopy.additionally, the thermal denaturation pattern of myofibrillar proteins was examined using Ca²⁺-ATPase activity, salt solubility, and SDS-PAGE as indicators. The results showed that the DSC analysis of fresh adductor muscle revealed three absorption peaks at temperatures of 50, 60 and 78 °C. After heating for 5 minutes, the absorption peaks at 50 °C and 80 °C were no longer detectable, suggesting they likely correspond to the thermal denaturation of myosin and actin, respectively. Following boiling treatment, the adductor muscle fibers in R. philippinarum demonstrated lateral aggregation and longitudinal contraction. This morphological change resulted in varying degrees of separation between the muscle and shell due to differential contraction rates. A specific heating regimen for myofibrillar proteins (0.5 mol/L NaCl at 45 °C for 5 min) led to a marked decrease in Ca²⁺-ATPase activity and salt solubility, indicating myosin thermal denaturation. Additionally, actin played a significant protective role over myosin before denaturation. The simultaneous denaturation of myosin, actin, and tropomyosin, which contributed to the facilitation of shelling. This study provided a scientific basis and data support for futher developing processing techniques for R. philippinarum.