Treatment of keratitis requires targeting the cause, actively controlling the infection, promoting healing, and reducing scar formation. Keratitis is classified according to the causative agent as infectious, immune, dystrophic, neuroparalytic, and exposure. Infectious keratitis mostly occurs in the central zone of the cornea, while immune keratopathy tends to occur in the peripheral part of the cornea. Among them, the most common is infectious keratitis. Infectious pathogenic microorganisms include bacteria, viruses, fungi, Echinococcus amebae, mycoplasma, chlamydia, syphilis spirochetes, etc. The basic principle is to take all effective measures to control the infection quickly, to strive for early cure, and to reduce the sequelae of keratitis to a minimum. Since most ulcerative keratitis is due to external causes, it is extremely important to remove the causative external causes and eliminate the causative microorganisms, applying antibiotic eye drops for bacterial infections and antibiotic eye ointment before bedtime; applying antiviral eye drops for viral infections. Corneal lesions related to systemic diseases should be treated actively in addition to ocular treatment. Conservative treatment is ineffective or the ulcer leaves a scar that significantly affects vision to perform corneal transplantation. Therefore, the treatment of keratitis varies depending on the cause.