Abstract: With the development of our country’s aquaculture industry, the amount of bay scallop farming is increasing year by year. Because of its high nutritional value and medicinal value, it is favored by consumers. Opening the shell is the focus of the processing of bay scallops. The closed shell muscles close the two shells inside, making it difficult to open the shell. In this paper, based on the research of bay scallop shell opening plan, combined with the physiological structure characteristics of bay scallop, the heat treatment opening plan of scallops is summarized, and the three heat treatment plans of fire roasting, water bath impact opening, and steam jet opening are tested, and the best is selected. The best heat treatment plan is the steam open shell method. The steam jet shelling device for bay scallop is designed. The size and installation position of the profiling hole and the forming knife in the key components are designed and analyzed. The single factor test is conducted with the steam jet time, steam jet distance, and steam valve opening as the test factors, and the sensory score of shelling effect as the index. The interactive test analysis of factors is conducted through Box-Behnken design. Finally, when the steam jet is 3 s, the jet distance is 30 mm, the opening of the steam valve is 90°, the opening effect is the best, and the sensory score is 93.67 points. Through the research on the opening plan, we can solve the difficult problem of opening the scallop, improve the dirty and messy situation of the scallop processing, fill the vacancy of the scallop processing plan in our country, and lay the foundation for improving the degree of mechanization of scallop processing in our country.