In the traditional harvesting operations of beach aquaculture enterprises, shellfish is raked and picked up by hand tools, the efficiency of which is rather low and there are potential safety hazards. In this study, a self-propelled beach shellfish harvester was designed composed of a walking traction and a collecting operator, and could catch the shellfish buried in sand when there was no water or shallow water. Sand containing shellfish on the beach would be scooped up and transported backward, and then cleaned by two-stage method. The sand leaked out in the process of transportation and cleaning, and small shellfish could also be screened out to the tidal flat surface to keep growing. The shellfish that meet the harvesting specifications were left in the collection box, and the mechanized harvesting was realized. The device prototype was tested in Rudong County. Results showed that, the maximum working depth of the harvester was more than 70mm, the production efficiency was 0.087 km2/h, the harvesting rate was 93.2%, and the crushing rate was 2.1%. This self-propelled shellfish harvester could meet the needs of beach aquaculture enterprises for better harvesting.