Microbial keratitis is one of the major causes of blindness in China. The rapid and unequivocal identification of the causative organism is the key point for the rational antimicrobial therapy and restoration of the vision. It is difficult for the physician to choice the first step in the management of microbial keratitis: starting antimicrobial therapy after the identification of the causative organism, or starting therapy even there is no organism identification. The authors thought that it is urgent to start the antimicrobial therapy for microbial keratitis, however, the causative organism identification should be performed in time. This steps are necessary for the high diagnostic rate and cure rate of microbial keratitis, also for improving physician's consciousness of causative organism diagnosis.