The invention relates to a plant material adsorbent for reducing the cadmium content of tobacco extracting liquid. The plant material adsorbent is prepared by adopting the steps: crushing root systems of pokeberry serving as raw materials; soaking the crushed materials into diluted acid and performing modification treatment; and filtering and then washing with deionized water to finally obtain the plant material adsorbent. The tobacco extracting liquid with the reduced cadmium content is obtained by adding the plant material adsorbent into the tobacco extracting liquid, adsorbing, and filtering and removing the plant material adsorbent. The plant material adsorbent has the advantages that the root systems of the modified cadmium hyperaccumulator plants, namely, pokeberry are used as the adsorbent, the cadmium content in the root systems of the pokeberry can reach 2 percent, the pokeberry has a large number of cadmium adsorption sites, and the adsorption sites of heavy metal of the pokeberry can be released through modification by diluted acid; the modified plant material is added into the tobacco extracting liquid and can adsorb the cadmium ions in the tobacco extracting liquid, and the possibility of adding non-plant components into the tobacco extracting liquid is avoided. The plant material adsorbent is simple in treatment process, easy to operate, low in cost and reusable.