The present invention discloses a method for expressing multiple recombinant proteins in transgenic non-human mammalian milk, characterized in which human clotting factor IX gene and porcine lactoferrin gene are transferred into the mammal by gene injection and embryonic implantation to obtain expression in the milk of transgenic mammal and its filial generation. The method of this invention can maintain the stable expression of multiple recombinant proteins in the transgenic mammal during lactation and stable expression amount proximate to that of the first generation in the offsprings of the transgenic non-human mammal.