ObjectiveTo investigate effect of application of thymopentin during perioperative period on immune function of patients undergoing laparoscopic assisted radical resection for rectal carcinoma. MethodsForty-two patients undergoing laparoscopic assisted radical resection for rectal carcinoma from January 2015 to April 2015 in this hospital were collected. These patients were divided into study group and control group. The patients were received routine treatment in the control group. In addition to routine treatment same as the control group, the patients were received 2 mg thymopentin every day for a week in the study group. The changes of lymphocyte count, T lymphocyte subsets (CD3+, CD4+, CD8+, and CD4+/CD8+), and immunoglobulin (IgG, IgA, and IgM) were compared on the 1st day before surgery and on the 1st day and 5th day after surgery. ResultsThe lymphocyte count, T lymphocyte subsets, and immunoglobulin on the first day after surgery were significantly lower than those on the 1st day before surgery in these two groups (P < 0.05). The lymphocyte count, T lymphocyte subsets (except for CD4+/CD8+), and immunoglobulin (except for IgA) in the study group were significantly higher than those in the control group on the 5th day after surgery (P < 0.05). The changes of lymphocyte count, T lymphocyte subsets, and immunoglobulin in the study group had no significant differences between on the 5th day after surgery and on the 1st day before surgery (P > 0.05), but which on the 5th day afer surgery were significantly lower than those on the 1st day before surgery (P < 0.05) in the control group. ConclusionApplication of thymopentin during perioperative period could accelerate recovery of immune function after operation in patients undergoing laparoscopic assisted radical resection for rectal carcinoma.