Abstract: Genetically modified pigs for welfare assurance is crucial for conducting xenotransplantation. However, traditional experimental animal ethics principles cannot address the social benefits issues brought about by xenotransplantation, and there is a lack of ethical justification for the assurance of experimental animal welfare. Degrazia and Bechtel proposed six principles for the welfare of experimental animals: the principle of no alternative methods, the principle of expected net benefits, the principle of adequate defense of harm, the principle of no harm without necessity, the principle of basic needs and the principle of harm limit. This paper conducts an ethical-level argumentation on the six principles for the welfare of genetically modified pigs in xenotransplantation, and points out that these six principles are of great significance in closely integrating the social benefits of xenotransplantation with the welfare of genetically modified pigs, emphasizing the moral status of genetically modified pigs, and providing standards for the ethical review of the welfare of genetically modified pigs.