Intraoperative floppy iris syndrome is a particular symptom in phacoemulsification, and it is often occurred in patients with the history of using alpha-1 adrenergic antagonist before cataract surgery. Although the pupil be fully mydriatic before the operation, the progressive constricting of the pupil, the relaxing of iris even the iridoptosis and the unstable anterior chamber still can be found during the phacoemulsification. If treated inappropriately, severe complications and terrible outcomes may happen,which would influenced the surgery effectives. This paper reviewed the epidemiological characteristics, pathogenesis, risk factors, clinical manifestations, complications, and coping strategies of the intraoperative floppy iris syndrome.