Objective　To study the causes of failure to IOL implantation during cataract surgery.Methods　We reviewed 540 eyes in which 23 eyes were failed to implant IOL during cataract surgery.Results　Detachment of suspended zonular ligament, rupture of posterior capsule and vitreous prolapse are the main factors influencing IOL implantation during cataract surgery.Conclusion　Improvement of surgical technique and reduction of complications are the key points for the IOL implantation successfully during cataract surgery.