Objective To investigate the invasion ability of Panc-1 cells in vivo and in vitro af ter being t ransfected with tissue factor pathway inhibitor 2 gene ( TFPI-2) . Methods The expression vector pEGFP-C1-TFPI-2 was transfected into human pancreatic cancer line Panc-1 cells by using liposome. TFPI-2 mRNA and protein of transfected and nontransfected cells were detected by reverse t ranscription-polymerase chain reaction (RT-PCR) and Western blot respectively. The tumor cells invasive behavior of t ransfected ( Panc-1-TFPI-2) and nontransfected ( Panc-1-V and Panc-1-P) cells were assessed in vitro through Boyden Chamber method. The transfected and nontransfected cells were implanted into nude mice to observe it s growth and metastasis in vivo. Results Expressions of mRNA and protein of TFPI-2 were confirmed in transfected cells. Af ter TFPI-2 t ransfection , the number of Panc-1-TFPI-2 , Panc-1-V and Panc-1-P cells passing through membrane of Boyden Chamber were 24. 4 ±3. 5 ,61. 3 ±4. 1 and 60. 2 ±3. 9 , respectively. The number of TFPI-2-expressing cells to t raverse a Matrigel-coated membrane was obviously decreased compared with that of non-expressing cells , the invasion ability was lower than that before transfection in vitro. The subcutaneous tumor volume of the Panc-1-TFPI-2 group was (438. 0 ±69. 8) mm3 , the Panc-1-V group was (852. 0 ±102. 9) mm3 and the Panc-1-P group was (831. 0 ±78. 1) mm3 , P lt; 0. 05. The metastasis to liver and lung and muscular invasion occurred in the Panc-1-V group and the Panc-1-P group. There were no muscular invasion and metastatic lesions in the Panc-1-TFPI-2 group. Conclusion TFPI-2 gene expression may obviously inhibit the invasion ability of pancreatic cancer cells in vitro and in vivo , which provides an experimental basis for the treatment of human pancreatic cancer by gene therapy.