Abstract: A microcontroller-based variable seeding control device was created based on a cone disk centrifugal shellfish seeding device to improve the survival and utilization rate of shellfish seedlings and satisfy the need for density changes in shellfish farming with various substrates. Created a feedback system using an STC89C51 microcontroller, design essential parts such as an actuator, feeding device, and variable control system, and implemented a precise variable seeding plan into action. We conducted a three-factor, three-level orthogonal test, with seedling dropping rate, impeller disc speed, and travel speed as influencing factors, and the coefficient of variation of seedling distribution uniformity and the relative error of seedling sowing amount as evaluation indicators. The findings demonstrated that the rotating speed was the primary factor influencing the coefficient of variation, while the dropping rate was the primary element influencing the relative error of the seedling sowing rate. A dropping rate of 0.8 kg/s, an impeller disc speed of 800 r/min, and a travel speed of 0.77 m/s were the ideal parameter combinations. At this point, the relative inaccuracy of the seedling sowing rate was 9.23%, and the coefficient of variation was 11.07%. We conducted the mudflat test. The mean relative error of the seeding quantity was 9.29%, and the mean error of the coefficient of variation was 9.36% when compared to the performance test. In addition to meeting the requirements for seeding precision and uniformity, the cone disk centrifugal variable seeding device proposed in this study demonstrated enhanced performance and offers a theoretical foundation for mechanical variable seeding of shellfish.