The global increase in plastic production, reaching 322 million tons in 2015 and projected to multiply by 2050, underscores the urgent need for sustainable alternatives. Biodegradable plastics, derived from renewable resources like starch, protein, and cellulose, offer an eco-friendly solution. Water hyacinth, rich in cellulose, presents potential as a raw material for biodegradable plastics. However, its rigidity, strength, and hydrophilicity necessitate improvements through additives. This study investigates the effects of sorbitol plasticizer, chitosan, and calcium silicate fillers on water hyacinth cellulose-based biodegradable plastics. Key tests include tensile strength, elongation, solubility, and biodegradability. Optimal compositions (cellulose 33.68%, chitosan 4.41%, calcium silicate 7.99%) achieved tensile strength of 15.97 MPa, 10.97% elongation, 52.5% solubility, and 21-day degradation. Characterization by FTIR, SEM, and XRD confirmed functional group changes, smoother surfaces, and reduced crystallinity. Further research should refine bioplastic molding methods.