The invention relates to long-acting veterinary 
ivermectin injection. Every 1000ml long-acting veterinary 
ivermectin injection contains 10-15g of 
ivermectin, 500-600ml 
propylene glycol, 200-300ml of absolute ethyl 
alcohol, 80-120ml of glycerolformal and 80-120ml of 
benzyl alcohol. A preparation method of the long-acting veterinary ivermectin injection comprises the following steps: 1) adding ivermectin and 
propylene glycol into absolute ethyl 
alcohol, stirring, and dissolving; and 2) adding glycerolformal and 
benzyl alcohol into the solution obtained in the step 1), uniformly stirring, maintaining constant volume, carrying out 
sterile filtration, and encapsulating, thus the long-acting veterinary ivermectin injection is obtained. The long-acting veterinary ivermectin injection is stable in quality, effect can last for 72 hours, anthelminthic effect is remarkable, 
insect bodies inside and outside 
livestock and poultry can be dispelled, and diseases like swine, bovine and ovine horned 
toad can be treated by only injecting the long-acting veterinary ivermectin injection once.