The invention relates to an ant killing agent and a preparation method thereof, wherein the ant killing agent contains the components of asarum, powdery boric acid, pine powder, honey, propolis, sugar and lean meat powder. The preparation method comprises the steps of material preparation and preparation, wherein the preparation is as follows: adding 60-degree hot water to a stirring tank, wherein the weight ratio of the added hot water to the pine powder is (0.75-0.88):1; and stirring while adding asarum, pine powder, lean meat powder, honey, propolis, sugar and powdery boric acid in the hot water of the stirring tank in sequence, and after stirring uniformly, sealing and packing the mixture to obtain a finished product. According to the ant killing agent and the preparation method thereof, on the premise of not harming other animals, the ant killing agent can effectively kill ants, can effectively reduce harm of ants, has definition on the ant dispelling range, is long in ant dispelling effect and pollution-free, has no harm to other animals, and has the advantages of being convenient to use, low in cost and easy to produce and prepare.