Abstract: Objective To evaluate the safety, tolerance and make sure the safe dose range of single dose and continuous hypodermic injection Recombinant Human Thymosin Alpha-1 （rh-thymosinα1） in Chinese healthy volunteers. Methods 48 healthy volunteers were received a single dose group, including 36 subjects hypodermic injection of 0.3 mg/m²,0.6 mg/m²,0.9 mg/m2,1.4 mg/m²,2.0 mg/m²,2.7 mg/m² rh-thymosinα1, 12 subjects hypodermic injection of the same dose water as placebo. 12 subjects in continuous dose group were hypodermic injected 2.0 mg/m² or 2.7 mg/m² rh-thymosinα1, two times a week, continue for four weeks. Safety and tolerance were evaluated by monitoring adverse events and laboratory parameters. Results 48 healthy volunteers actual finished in a single dose group. There were no adverse events taken place in a single dose group. 12 healthy volunteers actual finished in a continuous dose group. There were 5 adverse events taken place in a continuous dose group, including 3 subjects fecal occult blood（FOB）, 1 subject haemoglobinuria, 1 subject FOB and haemoglobinuria. All of them returned to normal after drug withdrawal in follow-up phase. Conclusion Rh-thymosinα1 from 0.3 mg/m² to 2.7 mg/m² hypodermic injection of single dose was safe and well tolerance. Continuous using for four weeks, two times a week and the dose in 2.7 mg/m² were safe.