The invention discloses medical disinfectant and a preparation method thereof. The medical disinfectant comprises, by weight, 16-20 parts of honeysuckle flowers, 10-14 parts of ceropegia pubescens, 8-12 parts of ardisia brunnescens, 7-11 parts of lychnis coronata, 4-8 parts of artemisia sphaerocephala, 2-6 parts of potassium iodide and 1-5 parts of oxytropis myriophylla. The medical disinfectant and the preparation method thereof have the advantages that the medical disinfectant is made from natural raw materials, including the honeysuckle flowers, the ceropegia pubescens, the ardisia brunnescens, the lychnis coronata, the artemisia sphaerocephala and the oxytropis myriophylla, added with the potassium iodide according to the preparation method; the prepared medical disinfectant has a goodsterilization effect, small irritation to the human body, no toxic and side effect, a simple preparation process and a low production cost, and the industrialized production is easily realized.