The invention provides application of manganese benzoate porphyrin in a preparation of a medicine for promoting diabetic corneal injury healing. In the application provided by the invention, the manganese benzoate porphyrin can release the mitochondrial DNA from the injury of the oxidative injury by playing the antioxidant free radical function, thereby playing the effect of healing diabetic corneal injury. The experiment proves that the manganese benzoate porphyrin (MnTBAP) can effectively inhibit the hyper-glucose group TKE2 cell ROS level, and can effectively improve the hyper-glucose induced TKE2 cell mitochondrial function dysfunction. In the STZ induced diabetic mice, a certain dosage of MnTBAP is injected under the conjunctiva after establishing a corneal epithelium curettage injury model, thereby effectively inhibiting the concentration of mice corneal epithelium ROS and inhibiting the 8-OHdG expression; and meanwhile, the GSH level of the corneal epithelium antioxidant and free radical scavenger of the diabetic mice can be improved, and the corneal epithelium injury healing of the diabetic mice is promoted.