The proposition of “Men as an end” has a powerful influence, but its application in bioethics is limited. The more widely used the proposition is, the easier it is to become superficial. Therefore, to clarify the connotation of “man as an end” is the precondition of proper application. The proposition of “Man as an end” derives from Kants “formula of humanity” whose central idea is to respect the moral ability of rational being. The transaction of organs violates the proposition of “man as an end”, because it impairs the integrity of life, damages the carrier of person, and thus degrades the moral ability of the rational subject. As far as the commercial surrogacy is concerned, it violates the proposition not because it undermines the integrity of life, but because it reinforces the tendency of viewing women merely as the instrument.