Objective: To evaluate the effect of ultrasound-guided thoracic paravertebral nerve block anesthesia on cognitive function in elderly patients with lung cancer undergoing thoracotomy.Methods:80 elderly patients with lung cancer treated in our hospital from January 2015 to December 2018 were divided into two groups,before anesthesia, the observation group (n=40) received ultrasound-guided paravertebral nerve block, while the control group (n=50) received epidural block,hemodynamic changes, postoperative pain and cognitive function were observed.Results:At the time points of T2-T5, MAP and HR in the observation group were significantly lower than those in the control group(P＜0.05),there was no significant difference in MAP and HR at T1 between the two groups(P＞0.05);After withdrawal, the average time for patients in the observation group to resume spontaneous breathing, swallowing and breathing was significantly shorter than that in the control group(P＜0.05);There was no significant difference in VAS score between the two groups at 6, 12, 24 and 48 hours after operation(P＞0.05);There was no significant difference in MMSE score between the two groups before and 48 hours after operation(P＞0.05),at 1h, 6h and 24h after operation, the MMSE score of observation group was significantly higher than that of control group(P＜0.05).Conclusion:When patients with lung cancer undergo thoracotomy,uitrasound-guided paravertebral nerve block was used,can keep the hemodynamics of patients in good stability, and the analgesic effect is ideal, and it will not have a significant impact on the cognitive function of patients after operation.