The invention provides a preparation for treating periodontosis. The preparation comprises 0.001-3wt% of an iodine preparation, 0.1-0.2wt% of a bactericide, 0.5-1wt% of nystatin, 0.25-0.5wt% of chlortetracycline hydrochloride, 0.05-0.15wt% of a steride anti-inflammatory agent, 0.05-0.1wt% of vitamin C, 0.01-0.03wt% of vitamin B1, 0.001-0.01wt% of vitamin B12, 0.2-1wt% of glycerin, 0.01-0.3wt% of one of indigo naturalis, calculus bovis factitius, felwort, amur corktree bark, borneol or menthol, and balance distilled water. The preparation has the advantages of simple operation, small patient pain, good compliance, no operation treatment, low cost, short treatment course, good treatment effects, and simple and convenient doctor operation.