Abstract: OBJECTIVE To explore the related factors of iatrogenic infections after vitrectomy. METHODS A total of 3473 patients underwent vitrectomy in hospital from Feb. 2012 to Feb. 2017 were selected, and the related factors of iatrogenic infection after operation were analyzed. RESULTS In 3473 patients, infective endophthalmitis occurred in 5 cases, and the incidence was 0.14%. The 5 cases were cultured pathogenic bacteria, including 4 strains of gram-positive bacteria and 1 strain of gram-negative bacteria. In 1321 cases of < 60 year old patients,there were 5 cases of postoperative infectious endophthalmitis, with the incidence of 0.38%, and in 2152 cases of ≤60 year old patients, there was 0 case of postoperative infectious endophthalmitis, and the difference was significant (P<0.05). In 1163 patients with chronic underlying diseases, there were 5 cases of postoperative infectious endophthalmitis, with the incidence of 0.43%, and in 2310 patients without chronic underlying diseases, there was 0 case of postoperative infectious endophthalmitis, and the difference was significant (P<0.05). In 5 patients with postoperative infectious endophthalmitis, 4 patients had good infection control, with partial recovery of vision, and the infection was controlled in 1 patient, but with a atrophy of the eyeball. CONCLUSION Iatrogenic infection after vitrectomy has a certain relationship with the patient's age and chronic underlying diseases, implementation of hospital infection control, perioperative aseptic operation, etc. can effectively prevent the occurrence of postoperative infection.