The invention discloses a plant source anti-bacteria type organic nutrient solution and a preparation method thereof. The plant source anti-bacteria type organic nutrient solution is prepared from a nutrient solution A and a nutrient solution B, wherein the nutrient solution A is prepared from biogas slurry and organic matter decomposed liquid, and the nutrient solution B is prepared from dandelions, houttuynia cordata, radix scutellariae, honeysuckles, radix isatidis and coptis chinensis. The preparation method comprises the steps that the nutrient solution A is prepared from the biogas slurry and the organic matter decomposed liquid; the dandelions, the houttuynia cordata, the radix scutellariae, the honeysuckles, the radix isatidis and the coptis chinensis are smashed, grinded and sieved, traditional Chinese medicine mixture fine powder is obtained and added into water to be soaked, sieving is conducted to remove impurities and residues, a rough filtered solution is obtained, sieving is conducted on the rough filtered solution, and the nutrient solution B is obtained; and the nutrient solution A and the nutrient solution B are mixed, namely the plant source anti-bacteria type organic nutrient solution is obtained. According to the prepared plant source type organic nutrient solution, organic components are used as raw materials completely, damage to the soil and environment does not exist, nutrition is rich, cost is low and the antibacterial effect is significant.