OBJECTIVE： To investigate the perioperative prophylactic use of antibiotics in thoracic surgery department of 7 hospitals in Nantong city， and to provide reference for rational drug use in clinic. METHODS： In retrospective study， 6 652 discharged patients with thoracic surgery were  selected from 7 “third-level hospitals” of Nantong city during 2015-2016. The gender， age， length of stay， preoperative medication， medication timing， classification of incision， operation time， drug name， usage and dosage， route of administration， drug combination and prognosis were analyzed statistically. According to the relevant regulations of special rectification and the principle of perioperative antibiotics use， the rationality of antibiotics use was evaluated.  RESULTS： Among 6 652 patients， there were 2 761 cases of typeⅠincision and 3 891 cases of type Ⅱ incision. All of them used antibiotics. Primary prophylactic time was 0.5-2 h before operation in 5 282 cases， accounting for 79.40％； 1 370 cases were given medicine more than 2 h before surgery or after surgery， accounting for 20.60％. Totally 1 070 cases received prophylactic medication within 48 h， accounting for 16.09％； 5 582 cases received prophylactic medication more than 48 h， accounting for 83.91％. A total of 5 702 cases were given only one antibiotic， and 950 cases received two-drug combination. A total of 6 342 patients used antibiotics irrationally， accounting for 95.34％. Eight categories 15 kinds of antibiotics were involved. β-lactam/β-lactamase inhibitors， fluoroquinolones and cephalosporins were mostly used. CONCLUSIONS： After the implementation of special rectification， there are still many irrational phenomena in the prophylactic use of antibiotics in thoracic surgery department of 7 hospitals in Nantong city. Some indexes exceed the national standard and still need to be further managed and improved.