Abstract: Objective： To evaluate the role of thymosin α1 in adjuvant chemotherapy for post-operative patients with advanced gastric carcinoma. Methods： A total of 57 post-operative patients with advanced gastric carcinoma, who were admitted to Min Hang District Center Hospital during January 2011 and June 2014, were enrolled and randomly allocated to testing group or control group. The testing group was given thymosin α1 on the basis of S-1 and oxaliplatin(SOX regimen) while the control group was given only SOX regimen. The clinical efficacy was evaluated after at least two treatment cycles, and treatment-related adverse reactions were observed after each treatment cycle. The progression-free survival time and the cumulative survival time were calculated by Kaplan-Meier analysis. Results： The efficacy for 54 patients was evaluable. There was no significant difference regarding recent overall response rate (ORR) and disease control rate (DCR) between the two groups. The incidence rates of adverse reactions such as nausea, vomiting and sensory neuropathy in the testing group were lower than those in the control group (P< 0.05)．The median progression-free survival time and the median survival time in the testing group were significantly longer than those in the control group (P< 0.05). Conclusions： The application of thymosin α1 in post-operative chemotherapy for patients with advanced gastric carcinoma can relieve the side effect of chemotherapy and prolong the survival time.