The invention discloses a charcoal/bentonite composite material, a preparation method and an application thereof and relates to the field of environmental protection and repairing. The invention aims to simplify the preparation method for the charcoal/bentonite composite material and guarantee the prepared charcoal/bentonite composite material having an excellent heavy metal adsorption effect. The preparation method for the charcoal/bentonite composite material comprises the step of charring the powdered waste potato peel in a dried premix by adopting a programmed temperature rising method for heating and reacting the mixed bentonite and potato peel under the inert gas shielding condition, thereby acquiring the charcoal/bentonite composite material. The charcoal/bentonite composite material is prepared according to the preparation method. The preparation method for the charcoal/bentonite composite material provided by the invention is used for preparing a soil heavy metal adsorbent.