To address the environmental pollution caused by the untreated discharge of laver processing wastewater and the inadequacy of traditional solid-liquid separation devices due to the unique adhesiveness of residual algae and impurities, a solid-liquid separation device for laver processing wastewater was developed. The working principle of this device was briefly described, and the structural dimensions of its core components were designed and calculated. A prototype was assembled for performance testing. With the separation rate and adhesion rate of laver processing wastewater as evaluation indices, and considering roller brush speed, filter mesh aperture, and backwashing movement speed as factors, a three-factor, three-level Box-Behnken experimental design method was used to conduct a quadratic orthogonal combination experiment. The results indicated that the optimal operating parameters were a roller brush speed of 476.28 r/min, a filter mesh aperture of 0.32 mm, and a backwashing movement speed of 0.007 m/s. Under these conditions, prototype testing achieved a separation rate of 84.12% and an adhesion rate of 4.71%, with no significant precipitates or suspended solids observed in the treated wastewater, meeting the requirements for solid-liquid separation. The study demonstrates that this solid-liquid separation device exhibits good separation performance, significantly reducing the risk of water and soil pollution from direct wastewater discharge and mitigating eutrophication issues, indicating promising prospects for widespread application.