To understand the infectivity by porcine endogenous retrovirus with porcine skin fibroblast cell in vitro and in vivo, porcine skin fibroblast cell established by our laboratory were co-cultured with neo/HEK293 cell for the infection of PERV in vitro, and were subcutaneously transplantated to SCID (severe combined immuno-deficiency) mice for the infection of PERV in vivo, laying the foundation for valuation of biologic safety of xenotransplantation. The event of neo/HEK293 cells infected by PERV occurred during co-culture of porcine skin fibroblast cells with neo/HEK293 cells, expanding the rang of the infection of porcine endogenous retrovirus. After pig cells transplantated subcutaneously in SCID mice, the microchimerism (78.57%) of pig cells occurred widely, and there was phenomena of integration of PERV provirus (85.71%) in several organs or tissues remote from the injected sites, indicating infection of PERV in SCID mice in vivo, yet, there is no evidence of active viral replication in analysis of PERV env RNA of these tissues or organs. The infectivity of porcine endogenous retrovirus with porcine skin fibroblast cells in vitro and in vivo were demonstrated in this study, and there is no evidence of active viral replication of PERV in vivo. It is an important event of biologic safety which attention must be paid to potential hazard of infectious interspecies transmission of PERV during xenotransplantation.