The present invention relates to a method of preparing an harmful insect repellent exclusively for a horse using herbal medicinal materials, the method which solves a problem that the horse sensitively responds to sounds of harmful insects by applying the harmful insect repellent onto the skin of the horse, thereby reducing that harmful insects approach the horse during using of the harmful insect repellent reduces that the horse receives a wound or lightly gets injured by reducing that the horse is bitten by the harmful insects enables the horse to smoothly carry out a horse riding or horse racing service by allowing condition of the horse to be maintained in a normal state through sufficient rest and enables a horse-rearing farmhouse to reduce costs through localization. According to the present invention, the method comprises: a step a) of extracting clove and Litsea cubeba Persoon c. respectively by using hydrodistillation to obtain extracted essential oil of clove and extracted essential oil of Litsea cubeba Persoon c. a step b) of diluting the extracted essential oil of clove and extracted essential oil of Litsea cubeba Persoon c. to 20% diluted solutions by using ethanol and a step c) of mixing 5 to 15 wt% of an essential oil of clove, 5 to 15 wt% of an essential oil of Litsea cubeba Persoon c., 70 to 90 wt% of anhydrous ethanol, and 0.02 to 0.06 wt% of butylated hydroxytoluene as an antioxidant.본 발명은 말의 피부에 도포하여 사용시 말에 해충이 접근하는 것을 감소시켜서 말이 해충의 소리에 민감하게 반응하는 것을 해소시키고, 말이 해충에 물리는 것을 감소시킴에 따라 말에 상처나 작은 부상을 입는 것을 감소시키며, 말로 하여금 충분한 휴식을 통해 컨디션을 정상 상태로 유지시켜서 승마나 경마서비스를 원활히 수행하고, 국산화를 통해 말 사육 농가로 하여금 비용 감소를 도모할 수 있도록 구성된 한방약재를 이용한 말 전용 해충퇴치제 제조방법에 관한 것이다.본 발명에 따른 한방약재를 이용한 말 전용 해충퇴치제 제조방법은, a) 정향과 산계초를 물증류법(hydrodistillation)을 이용하여 각각 추출하는 단계 b) 추출된 정향 정유와 산계초 정유를 에탄올을 이용하여 20%로 희석하는 단계 c) 중량%로, 정향 정유 : 5~15%, 산계초 정유 : 5~15%, 무수 에탄올 : 70~90%, 산화방지제(Butylated hydroxytoluene) : 0.02~0.06%를 혼합하는 단계로 이루어져 제조하는 것을 특징으로 한다.
