The invention discloses biological bacterium liquid for preventing and controlling dry snails. The biological bacterium liquid is prepared from the following raw materials in parts by weight: 15 to 25parts of a fermentation and biological distillation extracting solution, 5 to 15 parts of a compound bacterium agent and a proper amount of water. The fermentation and biological distillation extracting solution is prepared from the following raw materials in parts by weight: 4 to 6 parts of wild cercidiphyllum tree leaves, 6 to 8 parts of paper mulberry tree leaves, 6 to 8 parts of pine needles,2 to 4 parts of chilies, 6 to 8 parts of toona tree leaves and 2 to 4 parts of pericarpium citri reticulatae. The compound bacterium agent is prepared from the following raw materials in parts by weight: 2 to 4 parts of lactic acid bacteria, 1 to 3 parts of amino acid and 2 to 4 parts of bacillus. The invention further discloses a preparation method of the biological bacterium liquid for preventing and controlling the dry snails. The biological bacterium liquid for preventing and controlling the dry snails is prepared by adopting the fermentation and biological distillation extracting solution and the compound bacterium agent, and dissipates a grass flavor to effectively dispel the snails; crops are prevented from being damaged by the snails, the yield of the crops is improved and the biological bacterium liquid is green and environmentally friendly.