The invention relates to a traditional Chinese medicine liquorice root residue water treatment agent and a preparation method thereof, and belongs to the technical field of a water treatment agent. The traditional Chinese medicine of liquorice root residue water treatment agent is prepared through performing white-rot fungus fermentation on water decorated liquorice roots. The method comprises the concrete steps that 1, liquorice root residue is mixed with carbon sources and water, then, white-rot fungi are added for inoculation; fermentation is performed; 2, solids are filtered out from the fermentation products, then, the solids are dried and crushed to obtain the water treatment agent. The liquorice root residue is used as raw materials; biosorbents are prepared through solid fermentation; the traditional Chinese herbal medicine residue of the liquorice root residue is used for waste water treatment, so that the resource utilization rate is improved; the environment pollution is reduced.