Objective:To compare the effects of ultrasound-guided interscalene brachial plexus block and C5-6 nerve root block for analgesia after shoulder arthroscopy. Methods: In the study, 40 patients of ASA Ⅰ-Ⅱ were selected for elective general anesthesia to repair the shoulder ligament rupture in Peking University Third Hospital, who were randomly divided into two groups, respectively for the intermuscular brachial plexus block group (group I) and C5-6 nerve root block group (group C), n=20. The forty patients underwent ultrasound-guided brachial plexus block or C5-6 nerve root block before general anesthesia. Group I: 0.2% ropivacaine 10 mL was injected into brachial plexus intermuscular approach; Group C: 0.2% ropivacaine 10 mL was injected around the nerve roots of C5 and C6, and the ultrasound images showed that the liquid wrapped nerve roots. The time of sensory and motor block after puncture, operation time, the time of postoperative analgesia, numerical rating scale (NRS) scores at 1, 6, 12, and 24 h postoperatively and the finger movements were recorded. The adverse drug reactions and the patient satisfaction were recorded. The primary end point was the study of shoulder rest and movement pain in the patients with postoperative nerve blockage; the secondary end point was the patient’s limb movements and thepatient satisfaction. Results: The duration of analgesia was (571.50±70.11) min in group I and (615.60±112.15) min in group C, and there was no difference between the two groups (P>0.05). The static and dynamic NRS scores at 1, 6, and 12 h in group C were lower than those in group I (P<0.05). There was no difference in static and dynamic NRS scores between the two groups during 24 hours (P>0.05). There was a significant difference in grade of muscle strength between group C [5(4,5)] and group I [4(2,4)] in the patients with nerve block hind limb (P<0.01), and there were significant differences between the two groups’ sensation in the radial nerve group C [1(0,2)] and group I [2(1,2)], the median nerve group C [0(0,2)] and group I [2(1,2)], and the ulnar nerves group C [0(0,1)] and group I [1(1,2)] (P<0.01). There was no statistical difference between the two groups in the sencation of the shoulder, group C 2(1,2) and group I 2(1,2) , P>0.05. Compared with group I 8(6,9), group C 9(8,10) was a significant difference in satisfaction (P<0.01). Conclusion: Interscalene brachial plexus block and C5-6 nerve root block could satisfy the needs of analgesia after shoulder arthroscopy, but C5-6 nerve root blockage does not limit the limb activity, the numbness is less, and the patient’s satisfaction is higher.