Abstract： Objective： To observe the clinical effects of modified Baoyin Jian Prescription combined with Levothyroxine Sodium Tablets in treating postoperative differentiated thyroid carcinoma （DTC） with syndrome of stasisheat injuring yin. Methods： A total of 124 postoperative DTC patients with syndrome of stasis-heat injuring yin， treated at Luoyang Branch of Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine from January 2023 to January 2025，were selected and randomly divided into the control group and the observation group using the random number table method，with 62 cases in each group. Both groups received routine postoperative treatment. The control group received Levothyroxine Sodium Tablets additionally， while the observation group received modified Baoyin Jian Prescription in addition to the control group's treatment. Both groups were treated continuously for 12 weeks. Clinical effects， thyroid function indices [free triiodothyronine （FT3）， free thyroxine （FT4）， thyroid-stimulating hormone （TSH）]，traditional Chinese medicine syndrome scores，immune function indicators （CD3+，CD4+，CD8+） levels， and β2-microglobulin （β2-MG） levels were compared between the two groups before and after treatment. Results： After 12 weeks of treatment， the total effective rate in the observation group was higher than that in the control group （P＜0.05）. The serum FT3 and FT4 levels were increased （P＜0.05）， while serum TSH levels were decreased in both groups when compared with those before treatment （P＜0.05）；the observation group showed higher serum FT3 and FT4 levels and lower TSH levels than the control group （P＜0.05）. Traditional Chinese medicine syndrome scores were decreased in both groups after treatment （P＜0.05），and were lower in the observation group than in the control group （P＜0.05）. The levels of CD3+ and CD4+ were increased （P＜0.05）， while CD8+ levels were decreased in both groups when compared with those before treatment （P＜0.05）； the observation group had higher CD3+ and CD4+ levels and lower CD8+ levels than the control group （P＜0.05）. The serum β2-MG levels were decreased in both groups after treatment （P＜0.05） and were lower in the observation group than in the control group （P＜0.05）. Conclusion： Modified Baoyin Jian Prescription combined with Levothyroxine Sodium Tablets demonstrates significant effect in treating postoperative DTC with syndrome of stasis-heat injuring yin. It can effectively improve thyroid function and traditional Chinese medicine syndromes， regulate the systemic immune function， and alleviate tumor-related burden.