The invention discloses an external ointment for treating herpes zoster, which comprises the following raw materials in proportion by weight: 45 to 55 grams of gamboge, 15 to 25 grams of red orpiment, 8 to 12 grams of camphol, 4 to 6 grams of hydrargyrum, 8 to 12 grams of menthol, and 1,000 grams of vaseline. According to the proportion, the external ointment is prepared by gradually heating the Vaseline to 100 DEG C, lowering the temperature of the Vaseline to 60 DEG C, mixing the powdered red orpiment, the camphol and the menthol into the Vaseline, reducing the temperature of a mixture to 50 DEG C, adding the gamboge and the hydrargyrum into the mixture, grinding the mixture until mercury globules disappear, gradually cooling the temperature of the mixture to 30 DEG C, and bottling the mixture. The ointment can cure the herpes zoster in short time with single treatment, has stable healing efficacy and convenient use, has significant healing effects on patients suffering from xerosis cutis, pruritus and tinea manuum, has cure rate of over 98 percent, and has good healing effects on verruca acuminate, chancroid, syphilis and other venereal diseases.