Objective: To analyze the effect of thyroid-stimulating hormone (TSH) suppression therapy on sex hormone levels in patients undergoing postoperative treatment for thyroid cancer. Methods: A total of 40 patients undergoing postoperative thyroid cancer treatment were selected for data analysis. TSH suppression therapy was implemented during the postoperative period. Patients were grouped according to the TSH level: TSH < 0.1, 0.1 ≤ TSH < 0.5, and TSH ≥ 0.5. Results: Among male patients, there were no significant differences in sex hormone levels at different dosing times and TSH levels (P > 0.05). For female patients, testosterone levels at different dosing times showed no significant differences under the same circumstances (P > 0.05). The comparison of testosterone levels at different TSH levels over 5 years of TSH suppression therapy did not yield significant differences (P > 0.05). However, the comparison of testosterone levels within 5 years of TSH suppression therapy yielded significant differences (P < 0.05), with the lowest levels observed at 0.1 ≤ TSH < 0.5. Conclusion: The use of TSH suppression therapy in postoperative thyroid cancer treatment minimally affects sex hormone levels in male patients. However, it has a significant impact on female patients. Therefore, preoperative sex hormone testing is recommended, and postoperative monitoring should include regular sex hormone testing.