The invention discloses a preparation for degrading Verticilium dahliae in continuous cropping soil of eggplant, and a preparation method thereof. The method is characterized by comprising the following steps: grinding the following raw material components in part by weight: 1 part of asarum, 2 parts of radix sophorae flavescentis, and 2 parts of fructus cnidii with the grinder to the fineness of 40 meshes; fully mixing the three raw materials powder into a mixture, adding 10 parts of water, and pouring the mixture into a sealed plastic bag for decaying at 26 DEG C for 15 days; taking the decayed materials, adding 25 parts of 80 percent ethanol into the decayed materials, fully and uniformly mixing the mixture, keeping the mixture for 36 hours and then fully extracting the mixture; filtering the extract and storing the filtrate in a container; and taking the filtrate, adding 34 parts of water into the filtrate, and diluting and uniformly mixing the mixture to obtain the preparation. The method is characterized by environmental protection, no residue, no pollution to environment and farm products, and capacity of keeping high quality of farm products. The method has the advantages of no requirement of expensive instruments, easily controlled process, stable quality of preparation, low production cost, convenient use, and simple and easily controlled operation. Natural active ingredients in the product can promote growth of vegetables roots, make the plants keep good growth vigor, and is favor of the healthy growth of organs of products.