The invention discloses a method for repairing cadmium-polluted soil by crosslinking agent structure-modified algae. The method comprises the following steps: (1) after naturally air-drying algae, crushing, adding a cross-linking agent into the crushed algae, stirring while heating up to 40-60 DEG C, carrying out a reaction for 3-4 h, then cooling to the room temperature, continuing stirring for 1-2 h, removing the residual cross-linking agent, drying, and crushing into a soil repairing agent with the particle size of less than 40 mesh; and (2) applying the soil repairing agent on the surface of the cadmium-polluted soil, mixing evenly the soil repairing agent with the cadmium-polluted soil, and carrying out a reaction for 1-3 weeks. The algae modified by the crosslinking agent structure are used as a soil stabilization material, the heavy metal polluted soil is rapidly repaired in 1-3 weeks, and the repaired cadmium-polluted soil loses the bioavailability.