OBJECTIVE： To study the improvement effect of Z-Guggulsterone （Z-GL） on blood coagulation and vascular endothelial functions of acute blood-stasis model rats and its mechanism. METHODS： 40 rats were randomly divided into normal group， model group， positive group （Aspirin tablet， 50 mg/kg） and Z-GL low-dose and high-dose groups （25， 50 mg/kg）， with 8 rats in each group. They were given relevant medicine intragastrically every 12 h， and normal group and model group were given constant volume of normal saline intragastrically for consecutive 7 times. After the fifth administration， except for normal group， those groups were given adrenalin hydrochloride subcutaneously+ice-cold water to induce acute blood-stasis model. Within 30 min after the last administration， aorta abdominalis sample were selected to detect the coagulation parameters [prothrombin time （PT）， thrombin time （TT）， activated partialthromboplastin time （APTT）， fibrinogen （FIB）]， and pathological changes of carotid artery were observed. Human umbilical vein endothelial cells （HUEVCs） were divided into blank group （normal saline）， model group （normal saline） and Z-GL low-concentration and high-concentration groups （25， 50 μmol/L）. After culturing for 24 h， the cells were exposed to glucose and oxygen deprivation for 6 h in model group and Z-GL groups. The expression of p-eNOS protein was detected. Other cells were selected， grouped， administrated and treated as above cells， and the NO level of these cells were detected. RESULTS： Compared with normal group， PT， TT and APTT were all shortened in model group， while FIB content was increased （P＜0.01）； vascular endothelium was injured， and endothelial cells fell off from the wall. Compared with model group， PT， TT and APTT were prolonged in administration groups， while FIB content was decreased （P＜0.05 or P＜0.01）； vascular endothelium injury was relieved. Results of p-eNOS protein and NO levels determination showed that compared with model group， p-eNOS protein and NO levels were increased in Z-GL groups （P＜0.05 or P＜0.01）. CONCLUSIONS： Z-GL can significantly improve coagulation and vascular endothelium functions of blood-stasis model rats， and its mechanism may be associated with the activation of eNOS and the increase of NO level.