Objective To compare the resuscitation effect of 6% hydroxyethyl starch (HES) of different molecular weight in normal saline on hemorrhagic shock in rats. Methods Hemorrhagic shock model was established in 50 SD rats by 45% hemorrhage,and then they were equally divided into 5 groups. The rats were administered with HES40/,HES130/,HES200/normal saline,Voluven or Haes. Their mean arterial blood pressure (MAP),left intraventricular systolic pressure (LVSP),the maximal change rate of left intraventricular pressure (?dp/dtmax) of hemorrhagic shock rat were observed. Meanwhile,the artery blood gas,the survival time and 24-hour survival rate were also observed. Results Similar hemodynamic parameters values were obtained in the rats treated with our HES and those with Voluven or Haes. HES130 and HES200 prolonged the survival time of shocked animals in comparison with HES40. Among the 3 types of HES,HES200 had the best effect,which is equivalent to Voluven and Haes. Conclusion HES of 3 molecular weights have beneficial effect on hemorrhagic shock,and HES200 exerts best.