OBJECTIVE： To provide reference for standardize infusion interval time of time-dependent antibiotics. METHODS： In cross-sectional study， 336 inpatients receiving time-dependent antibiotics were randomly selected from our hospital in May 28th， 2015. The infusion interval of time-dependent antibiotics was investigated and analyzed to find out the problems， analyze the causes and put forward the improvement measures. RESULTS： Most of the time-dependent antibiotics used in our hospital are β-lactam antibiotics. 84.62％ time-dependent antibiotics of the bid infusion interval was lower than 8 h； the proportion of patients with nonstandard infusion interval of bid and regalar use （q8 h or q12 h）（68.75％ vs. 4.17％），with statistical significance （P＜0.05）. There was great difference in the incidence of nonstandard infusion interval among different departments and wards. It may be associated with physicians， nurses， departments and other medical conditions.  CONCLUSIONS： The infusion interval time of time-dependent antibiotics is too short in the inpatients of our hospital， and nonstandard infusion interval is serious； it is suggested to strengthen management， education and training from physicians， nurses and departments， so as to guarantee the safety and effectiveness of drug use.