To investigate the effect of oxycodone hydrochloride for preemptive analgesic on the inflammatory factors, NRS score, cortisol level, and immune function of patients with abdominal hysterectomy. Methods: From October 2016 to September 2019, 76 patients who underwent abdominal hysterectomy were selected and were randomly divided into control group and study group (38 cases in each group). 15 minutes before the induction of anesthesia, the patients in the control group were intravenously injected with 10 mL of 0.9% sodium chloride injection, and the patients in the study group were intravenously injected with 0.1 mg/kg of oxycodone hydrochloride injection. The other treatment for patients in the two groups was similar. The operation time and blood loss, intraoperative bleeding volume, and the levels of inflammatory factors, NRS, and cortisol, and immune function 15 minutes before anesthesia, 12 hours after anesthesia, and 24 hours after anesthesia of patients were compared between the two groups. Results: There were no significant different in operation time (67.5±9.4 min vs. 64.8±7.3 min) and blood loss (105.6±14.1ml vs. 108.5±16.4ml) of patients between the two groups (P>0.05). At 12 hours and 24 hours after surgery, the levels of inflammatory factors and cortisol, as well as the NRS scores of patients in the two groups had increased significantly, but those of patients in the study group were significant lower than those of patients in the control group (P<0.05). At 12 hours and 24 hours after surgery, the levels of the immune function indexes of patients in the two groups had decreased significantly, but those of patients in the study group were significant higher than those of patients in the control group (P<0.05). Conclusion: Oxycodone hydrochloride for preemptive analgesia of patients with abdominal hysterectomy can significantly reduce their levels of inflammatory factors and cortisol, can relieve their postoperative pain, which is conducive to the recovery of postoperative immune function of patients.