The present invention discloses a grass carp enteritis treatment drug composition, which contains, by weight, 10-30 parts of humulus scandens, 20-30 parts of humifuse euphorbia herb, 2-10 parts of melia azedarach leaf, 20-25 parts of heartleaf houttuynia herb, 2-10 parts of arborvitae leaf, and 2-7 parts of garlic. The invention further discloses a preparation method for the drug composition. According to the grass carp enteritis treatment drug composition, honeysuckle provides an anti-pathogenic microorganism effect, a certain inhibition effect is provided for a variety of pathogenic bacteria such as staphylococcus aureus, hemolytic streptococcus, escherichia coli, shigella dysenteriae, vibrio cholerae, typhoid bacillus, paratyphoid bacillus and the like, and a certain inhibition effect is further provided for pneumococcus, meningococcus, pseudomonas aeruginosa, and tubercle bacillus. The preparation method is simple and easy to perform, and is suitable for mass production.