To date, biochar bacteriostatic material has attracted much attention from researchers. The compact porous structure of fish-scale biochar provides good application prospects. In this study, silver-carrying biochar−polyvinyl alcohol−alginate gel beads (C/PVA/SA) were designed for suppressing bacteria. The biochar was loaded with nano silver particles as the filler, alginate as the substrate, and polyvinyl alcohol (PVA) as the additive to enhance the mechanical properties. The composite gel beads were characterized using Fourier-transform infrared spectrometry (FT-IR). The results indicated that adjusting the PVA concentration could retain the bacteriostatic performance of the gel beads in different pH value solutions. It was found that C/PVA/SA gel beads had a strong inhibitory effect on Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. After ten consecutive antibacterial tests, the antibacterial rate remained high (above 99%) for 15 days. The adhesive effect of SA and PVA resulted in a tight spatial structure of the gel beads. The C/PVA/SA gel composition could effectively prevent water loss and enhance the shrinkage ability of the gel beads. The good degradation performance of C/PVA/SA was also in line with the concept of environmental protection. In general, the C/PVA/SA gel beads showed high potential for application in the treatment of microbial contamination and environmental protection.