In order to establish pig induced pluripotent stem cells (iPS) with defined factor fusion protein, four defined factors genes Oct4, Sox2, c-Myc and Klf4 were delivered into porcine fetal fibroblasts by lentiviral transfection. The porcine fetal fibroblasts expressed exogenous defined factor genes were sub-cultured, and the clear-cut cell clones were gradually isolated. The cell colones grew at similar rates and stability, exhibited normal karyotype, and expressed alkaline phosphatase, Oct4, Nanog and SSEA1. And these cells could differentiate into various kinds of tissue in teratomas. The results confirmed that the isolated cell clones were iPS cells. This would greatly facilitate the further improvement of the induction protocol and in-depth study and application of pig iPS cells.