Abstract: A porous biological polymerizing agent for sediment dewatering in environmental dredging of rivers and lakes is disclosed, which is obtained by thoroughly mixing 50 wt % to 70 wt % of an agent A and 30 wt % to 50 wt % of an agent B into irregular spheres of 1 mm to 3 mm, and crushing the irregular spheres into solid particles with a particle size of ?20 mesh, and the solid particles have a pH of 5.0 to 6.0. The agent A is obtained by thoroughly mixing 10 wt % to 30 wt % of cellulose, 20 wt % to 50 wt % of starch, and 20 wt % to 40 wt % of amino acid; and the agent B is obtained by thoroughly mixing 40 wt % to 70 wt % of saccharifying enzyme (SE) and 30 wt % to 60 wt % of citric acid.