This study examined the expressions of human serum tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and their clinical significance. The serum TFand TFPI levels were detected by ELISA in 28 allo-HSCT recipients before and after the transplantation and the changes of TF and TFPI levels were dynamically monitored at different phases of the disease. No significant differences in the serum TF and TFPI levels were found in allo-HSCT recipients in the absence of aGVHD or with grade Ⅰ aGVHD before and after the transplantation. The levels of serum TF and TFPI were substantially increased in the patients with grade Ⅱ aGVHD at the peak of aGVHD (P＜0.05) and they were even higher in the patients with grade Ⅲ-Ⅳ aGVHD (P＜0.01). When the conditions became stable after treatment with immunosuppressive agents,the serum TFPI level was decreased to the baseline level (P＞0.05) and the TF level was lowered but still higher than the baseline level (P＜0.05). It was concluded that the levels of serum TF and TFPI were increased significantly in the patients with grade Ⅱ-Ⅳ aGVHD after allo-HSCT and decreased markedly after the treatment. Monitoring the levels of serum TF and TFPI in the patients with allo-HSCT is important to predict the occurrence,outcome and prognosis of aGVHD.