Objective To investigate the effect of fascia iliaca compartment nerve block (FICB) to early analgesia and emergence agitation for children after the operation of femur fractures, and compare with fentanyl. Methods Totally 36 cases of children, which scheduled for the one-sided femur fractures surgery were selected after the approval from the Institutional Review Board of the hospital. They were randomly divided into two groups: FI group (FICB group) and FE group (Intravenous fentanyl group). Patients in both groups were received ultrasound guided FICB immediately after the induction of general anesthesia, 1 ml/kg ropivacaine (Naropin) was given in the FI group and 1 ml/kg saline in the FE group, sevoflurane was used for the anesthesia maintenance and 1 μg/kg intravenous fentanyl in FE group, instead of the same volume saline in FI group at 10 min before the surgery finished, and patients were sent to postanesthesia care unit (PACU) after extubation. Keep a record of the duration of the operation and extubation, the pain scores and the Pediatric Agitation and Emergence Delirium (PAED) scores were recorded at just arrived at PACU (T0), 10 min (T1), and 20 min (T3) after PACU, also included the duration in PACU and the postoperatively side effects. Results At the time of T0 and T1, the pain scores in FI group was significantly lower than the FE(P 0.05), but it was still lower in FI group from the age of 8 to 14(P<0.05); The PAED scores at the three time points were always lower in FI group when it was compared with FE group; the same trend occurred for the duration of extubation and PACU(P<0.05). Conclusions FICB can effectively reduce emergence agitation and the pain scores for the children undergoing the surgery of femur fractures during the early time after the operation, which is better than the intravenous fentanyl. Key words: Nerve block/MT; Fascia/SU; Ilium; Femoral fractures/SU; Analgesia