Objective To explore the impact of recombinant human growth hormone （rhGH） on T lymphocyte subsets in patients with rheumatic heart disease during the perioperative period of heart valve replacement. Methods A total of 65 patients with rheumatic valvular heart disease who received heart valve replacement in Department of Cardiothoracic Surgery of Xiangyang Central Hospital from June 1， 2011 to March 31， 2012 were enrolled in this double-blind randomized controlled clinical study. All the patients were divided into 2 groups by random number produced by SAS software：the trial group and the control group. There were 35 patients in the trial group including 19 males and 16 females with their average age of 50.57 years， and 30 patients in the control group including 16 males and 14 females with their average age of 49.87 years. Apart from routine cardiac glycosides， diuretics， glucose-insulin-potassium solution， and postoperative anti-infective therapy， patients in the trial group also received subcutaneously injection of rhGH 5 U （1 ml）daily from 1 day before surgery to 3 days after surgery， and patients in the control group received subcutaneously injection of normal saline 1 ml as placebo. Peripheral venous blood samples were taken in the morning 2 days before surgery and 1 st， 3 rd， 7 th day after surgery respectively. Percentages of CD3+， CD4+， CD8+ were examined timely by flow cytometry and CD4+ /CD8+ ratio was calculated. Results In the control group， percentages of CD3+， CD4+ and CD4+ /CD8+ ratio on the 1st， 3rd， 7th postoperative day were significantly lower than preoperative levels， and percentages of CD8+ on the 1st and 3rd postoperative day were significantly lower than preoperative level （P＜0.05）. In the trial group， percentages of CD3+， CD4+， and CD8+ on the 1st and 3rd postoperative day were significantly lower than preoperative levels（P＜0.05）， while percentages of CD3+， CD4+， and CD8+ on the 7th postoperative day were not statistically different from preoperative levels （P＞0.05）; CD4+ /CD8+ ratio on the 1st postoperative day was significantly lower than preoperative level （P＜0.05）， while CD4+ /CD8+ ratios on the 3rd and 7th postoperative day were not statistically different from preoperative level （P＞0.05）. There was no statistical difference in preoperative T lymphocyte subsets between the trial group and the control group （P＞0.05）. The percentages of CD4+ and CD4+/CD8+ ratio in the trial group were significantly higher than those of the control group on the 1st postoperative day （P＜0.05）， while the percentages of CD3+ and CD4+ and CD4+ /CD8+ratio in the trial group were significantly higher than those of the control group on the 3rd and 7th postoperative day（P＜0.05）. Conclusion Use of rhGH can significantly increase T lymphocyte subsets expression， enhance body cellular immunity， and improve postoperative recovery of patients with rheumatic valvular heart disease during the perioperative period of heart valve replacement.