Abstract: Objective To evaluate the optimum dose of oxycodone for prevention of catheter related bladder discomfort (CRBD)during recovery period from general anesthesia with radical thyroidectomy. Methods One hundred and fifty male patients who underwent radical thyroidectomy in the First Center Hospital of Baoding from December 2015 to May 2017 were included in this study. All the patients were classified as ASA physical statusⅠ-Ⅱ, and randomly divided into five groups with 30 in each group:control group (group C), oxycodone 0.03 mg/kg group (group O₁), oxycodone 0.06 mg/kg group (group O₂), oxycodone 0.09 mg/kg group (group O₃) and oxycodone 0.12 mg/kg group (group O₄). At 15 minutes before the end of surgery, oxycodone was intravenously injected at dosage of 0.03 mg/kg, 0.06 mg/kg, 0.09 mg/kg, 0.12 mg/kg in group O₁, group O₂, group O₃ and group O₄, respectively. And 15 ml 0.9% NaCl solution was intravenously injected in group C. The occurrence and severity of CRBD at 4 h after surgery, and the occurrence of dizziness, respiratory depression and nausea and vomiting were observed and recorded. Results Severity of CRBD decreased accordingly in group C, group O₁, group O₂, group O₃ and group O₄, and significant differences were found between each two groups (P< 0.05) except group O₁ vs group O₂, and group O₃ vs group O₄. Compared with group O₄, the incidences of dizziness, respiratory depression and nausea and vomiting were significantly lower in group C, group O₁, group O₂ and group O₃ (P< 0.05). Conclusion The optimum dose of oxycodone for prevention of CRBD during recovery from general anesthesia is 0.09 mg/kg.