The present invention relates to a recombinant vector comprising MJ1 gene coding an integrase derived from Enterococcus temperate bacteriophage .phi. FC1 and an integration method using the vector. More particularly, the present invention relates to a recombinant vector comprising MJ1 gene which can make a site-specific integration in the human cell independently without other factors but not cause an excision and an integration method using the vector. Therefore, the present invention can be very useful in gene therapy in mammalian animal.