Abstract: OBJECTIVE To observe the microcirculation of lower limbs and microbiological detection of patients with nosocomial infection after hip replacement so as to provide guidance for prevention and control of the nosocomial infection after hip replacement. METHODS From Jan 2015 to Jul 2016, totally 24 patients who underwent the hip replacement and had the postoperative nosocomial infection were chosen as the observation group, meanwhile, 24 patients who underwent the hip replacement but did not have postoperative infection were set as the control group. The indexes of microcirculation of lower limbs were detected and compared between the two groups of patients, the indexes of microcirculation of lower limbs were also compared among the patients with different sites of infection, and the distribution of pathogens was observed and compared among the patients in the observation group. RESULTS The foot-nail fold microcirculation weighted integral loop week integral of the observation group was (1.10±0.12), significantly higher than (0.59±0.05) of the control group; the loop morphology integral of the observation group was (1.35±0.14), significantly higher than (0.80±0.07) of the control group; the total integral of the observation group was (2.93±0.21), significantly higher than (1.87±0.13) of the control group; other foot-nail fold microcirculation indexes of the observation group were better than those of the control group; the foot-nail fold microcirculation indexes of the patients with surgical site infection were worse than those of the patients with other sites of infection. A total of 39 strains of pathogens were isolated from 24 patients with infection, the proportion of the gram-positive bacteria was significantly higher than that of the gram-negative bacteria, and there was significant difference (P<0.05). CONCLUSION The patients with nosocomial infection are in a poor state of microcirculation of lower limbs after the hip replacement, however, the isolation rate of gram-positive bacteria is relatively high in this group of patients, to which great attention should be paid.