The invention discloses a medical disinfectant ultrasonic coupling agent and a preparation method thereof, which belong to the technical field of medical ultrasonic. The ultrasonic coupling agent is prepared from the following raw materials: polyethylene glycol, sodium carboxymethylcellulose, herba eupatorii volatile oil, Mosla chinensis Maxim volatile oil, folium artemisiae argyi volatile oil, rhizoma chuanxiong extract, radix scutellariae extract, herba senecionis scandentis extract, radix isatidis extract, radix arnebiae seu lithospermi extract, radix saposhnikoviae extract, Carbomer, triclosan, absolute ethyl alcohol, propyl p-hydroxybenzoate and purified water. The ultrasonic coupling agent is aromatic in fragrance, has a sterilizing and disinfectant effect, does not damage a probe, is non-irritating to the skin and free from allergenicity, avoids the cross infection of the clinical ultrasonic examination, does not pollute clothes, and is easy to clean, low in cost and good in stability; moreover, the medical disinfectant ultrasonic coupling agent is good in conduction effects, good in lubricating performance, easy to unfold, and good in safety, imaging effects and image resolution.