Wild thick shell Mytilus coruscus in the length range of 85~110 mm was taken as the research object to explore the characteristics of shell model of Mytilus coruscus. After obtaining corresponding sample point cloud file by optical scanner, geomagic wrap software was used to process and optimize the point cloud data to obtain a 3D sample model with good quality. Matlab software was used to fit the 3D sample model to obtain the best fitting model - standard model, and the standard model was digitized to obtain the mathematical function relations of the standard model outer shell surface (W) and inner shell surface (N). By examining the errors among the digital model, standard model and sample model, it was concluded that the average error among the three models was no more than 0.06 mm. Therefore, the digital model could be used to replace the sample model to guide the design of orienting and fixing device parts of Mytilus coruscus and plan the optimal Mytilus coruscus meat stripping route, so as to lay a theoretical foundation for building a modern Mytilus coruscus processing line.