Abstract: OBJECTIVE To analysis the utilization in patients in order to promote rational use of antimicrobial agents before and after intervention. METHODS By retrospective study, the use and ADR of aztreonam in outher’s hospital during April to June period of 2012 and 2013 were analyzed. RESULTS Before intervention, in some cases, the use of aztreonam was irrational in drug choice, dosage, administration and drug combination, etc. After intervention, the use of aztreonam in outher’s hospital was rational, the incidence of ADR was 0.67%. CONCLUSION The intervention on clinical use of aztreonam achieved remarkable outcome, unreasonable use of aztreonam reduced significantly after intervention.