The invention relates to an antiparasitic closantel sodium transdermal solution for ox and sheep and a preparation method thereof, the composing components of the solution and the parts by weight thereof are respectively that 5-15 parts of ethyl acetate, 20-30 parts of dimethyl sulfoxide, 2-6 parts of azone, 1-3 parts of isopropanol and 50-70 parts of propanediol or ethanol, the content of closantel sodium is 2.5-5 g per 100 ml, and the finished product is formed through dissolving, mixing, filtering and injecting. The azone related in the solution is a novel skin penetration accelerant, can effectively increase the absorption of the skin to various drugs through the skin, effectively prevents the pass effect of hepar, avoids the peak valley phenomenon during the absorbing process of the drugs, reduces the toxic side effect caused by about the drugs and the dosage, prolongs the effective acting time, changes the drug feeding area and effectively regulates the drug feeding dosage, reduces the difference between independent bodies, and has the characteristic of simple, convenient and rapid use. Compared with the other types of preparations, the solution is more suitable for antiparasitic preventive treatment and parasite killing in pasturing areas.