The present invention provides a plant activity composition for drug-free cultivation and an extraction method thereof, with which medicinal materials, such as indigowoad root, rhizome of Chinese goldthread, comfrey, hawthorn, and licorice are extracted respectively through water, ethanol, and ethyl acetate solvents, so as to obtain the extract of each medicinal material after being concentrated and mixed. These medicinal materials can be mixed first and then extracted or can be extracted first and then mixed to obtain the plant activity composition. Furthermore, it is applicable to combine the medicinal materials with dandelion, root of membranous milk vetch, or probiotics. By utilizing the bacteriostatic plant active ingredients and the cooperation enhancement effect provided by the combination ratio of the extracted plant activity composition, the present invention not only enhances the immunity of animals, but also possesses an excellent feed conversion rate, so as to provide a natural, drug-free and healthy cultivation condition.
