Objective:To explore the effect of ultrasound-guided nerve block combined with dexmedetomidine (DEX) on postoperative oxidative stress in patients with hip fracture and diabetes.Methods:From March 2017 to December 2019, 78 patients with diabetes who underwent hip fracture surgery were enrolled and divided into two groups by random number table method, with 39 cases in each group. After the operation, the control group was treated with ultrasound-guided femoral nerve combined with lateral femoral cutaneous nerve block with 0.375% ropivacaine, and the study group was treated with ultrasound-guided femoral nerve combined with lateral femoral cutaneous nerve block with 0.375% ropivacaine and DEX 0.5 μg/kg. Patients in both groups were received patient controlling intravenous analgesia (PCIA) after the operation, and visual analogue scoring (VAS) was used to evaluate the resting pain score of the patients at 4 h (T 1), 8 h (T 2), 16 h (T 3), 24 h (T 4), 36 h (T 5) and 48 h after operation (T 6). The levels of serum superoxide dismutase (SOD), malondialdehyde (MDA), 8-hydroxydeoxyuridine (8-OHdG), at T 1 and T 6 were compared between the two groups. The management system of continuous glucose monitoring system (CGMS) was used to calculate the mean amplitude of glycemic excursions(MAGE), largest amplitude of glycemic excursions (LAGE), absolute means of daily differences (MODD) of the patients during 48 h after operation, and the correlation between the blood glucose fluctuation indicators and the oxidative stress of the study group were compared. Results:The scores of VAS in the study group at T 1-T 6 were lower than those in the control group , the difference were statistically significant ( P<0.05). At T 6, the level of serum SOD in the study group was higher than that in the control group: (79.58 ± 13.55) kU/L vs. (64.16 ± 11.95) kU/L; the level of serum MDA and 8-OhdG in the study group were higher than those in the control group: (4.36 ± 0.81) μmol/L vs. (5.64 ± 0.94) μmol/L, (1.06 ± 0.19) μg/L vs.(1.42 ± 0.22) μg/L, the differences were statistically significant ( P<0.05). The levels of MAGE, LAGE, MODD in the study group were lower than those in the control group: (2.42 ± 0.47) mmol/L vs. (5.19 ± 0.96) mmol/L, (3.47 ± 0.64) mmol/L vs. (7.61 ± 1.32) mmol/L, (1.21 ± 0.27) mmol/L vs. (2.74 ± 0.46) mmol/L, the differences were statistically significant ( P<0.05). The correlation analysis showed that the blood glucose fluctuation indicators MAGE, LAGE and MODD of the study group were negatively correlated with SOD, and were positively correlated with MDA, 8-OHdG ( P<0.05). Conclusions:The use of ultrasound-guided nerve block combined with dexmedetomidine (DEX) for patients with hip fracture and diabetes can improve the analgesic effect, reduce oxidative stress of the patients, and improve the blood glucose fluctuation indicators.