The invention relates to a solidifying agent for stabilizing heavy metal Zn in soil and a using method thereof, and belongs to the technical field of environmental engineering. The solidifying agent for stabilizing the heavy metal Zn in the soil and the using method thereof are provided for aiming at the problems that according to solidification stabilization methods in the prior art, the amount of a solidifying agent is too large, cracking of a solidified body may be caused due to the effect of a long-term stress load and wet and dry cycle to accelerate leaching of heavy metal ions in the solid, and the environmental risk is high. First, a natural plant part with heavy metal Zn attraction effect is fermented for extraction of useful components, then carbonized bamboo particles are used as a carrier for adsorption of fermentation extract, and finally, the fermentation extract is mixed with vermiculite and other materials for preparation of the solidifying agent for stabilizing the heavy metal Zn in the soil for use. The solidifying agent is stable in Zn metal solidification, may not seep out, and has no harm to the environment.