By aiming at the problem of too slow medicine release of ivermectin oil injection prepared from benzyl benzoate and castor oil, the invention provides anti-parasites injection prepared by adding a certain amount of glyceryl triacetate into benzyl benzoate and castor oil, so that the fast-acting performance of the preparation is improved; in addition, the preparation still has the good long-acting effect. 0.1 to 10 percent (weight/volume ratio) of ivermectin medicine and cosolvents prepared from benzyl benzoate, glyceryl triacetate and castor oil are contained in the injection provided by the invention; in the cosolvents prepared from benzyl benzoate, glyceryl triacetate and castor oil, the volume percentage of the glyceryl triacetate is 10 to 38 percent; the volume percentage of castor oil is 15 to 40 percent; the balance is benzyl benzoate. Antioxidants and local analgetics can also be added in the injection.