Objective. To investigate the anesthetic effect of anterior serratus muscle plane block under ultrasound guidance in arthroscopic shoulder surgery and its effect on postoperative analgesia. Methods. A total of 94 patients who received arthroscopic shoulder surgery in our hospital were selected as the research subjects, and they were divided into a control group and a study group according to the random number table method. The control group underwent brachial plexus block under ultrasound guidance, and the study group underwent anterior serratus plane block under ultrasound guidance. The visual analogue score (VAS) of pain at each time point, intraoperative anesthetic dosage, the use of postoperative analgesic, pain mediators and oxidative stress factors before and after surgery, and the occurrence of adverse reactions were compared between the two groups after surgery. Results. At 6, 12, 48, and 72 h after surgery, there was no obvious difference in the VAS score between the two groups ( P > 0.05 ); 24 h after surgery, the VAS score of the study group was significantly lower than that of the control group ( P < 0.05 ). The intraoperative dosage of propofol and remifentanil in the study group was significantly lower than that in the control group ( P < 0.05 ). The number of effective compressions of analgesic pump and the total amount of sufentanil in the study group were significantly lower than those in the control group within 48 hours after operation, and the time of first compressions of analgesic pump was significantly longer than that in the control group ( P < 0.05 ). Before surgery, there were no significant differences in CGRP, NPY, and MDA levels and SOD enzyme activity between the two groups ( P > 0.05 ). After surgery, the levels of pain mediators CGRP and NPY in the study group were lower than those in the control group ( P < 0.05 ). The level of MDA was lower than that of the control group, and SOD enzyme activity was higher than that of the control group ( P < 0.05 ). There was no significant difference in the incidence of adverse reactions between the two groups ( P > 0.05 ). Conclusion. Ultrasound-guided anterior serratus plane block for arthroscopic shoulder surgery has a good anesthesia effect and long action time. It can significantly reduce the dosage of opioids, enhance the postoperative analgesic effect, effectively inhibit postoperative pain and oxidative stress reaction, and has good safety.