Pseudomonas aeruginosa keratitis can be described as one of the most common keratitis in clinical practice. It is characterized by an acute onset, fast development and hard to be treated entirely. Once failed to get prompt treatment, it would cause corneal ulcer, in an extreme case, blindness. In order to enhance the probability of treatment, it is meaningful to study the pathogenesis of pseudomonas aeruginosa keratitis further. The article reviews the pathogenicity of pseudomonas aeruginosa, and how the immunoreaction of host works in the pathogenesis of pseudomonas aeruginosa keratitis, thereby to provide theoretical basis of new methods for the treatment of pseudomonas aeruginosa keratitis.