Abstract: The revolution in biotechnology has redefined “human life” but challenges traditional philosophical thinking about what a human being is, and Kant’s proposition that “human being is the end” faces difficulties and challenges. How does Kant’s theory of dignity based on rationalism accommodate the new ethical identity, and how to justify “moral status of nonrational beings” have become new problems for ethics. Within the framework of Kant’s deontological ethics, Wood breaks the dichotomy between “person” and “thing” by reconstructing the value theory of the formula of humanity, completes the extended argument for the transition from “human being is the end”to “thing is the end” under the concept of logocentrism, and finally introduces the “the moral status of nonrational beings” and the “the direct duties regarding animals”. However, Wood’s reconstruction and expansion of the value theory is at the expense of abandoning the personification principle, which causes the separation of humanity and personality and weakens the moral subject status of the responsible person. In fact, on Kant’s view, “human being is the end” is a “moral imperative” that does not depend on the premise of value theory. Freedom and dignity are first a “duty”, not a “value” or “right”. Therefore, we have to hold on to the foundation of human dignity and nature of human freedom, insist on a “the responsible person” perspective, and construct and expand the horizon of ethical concerns based on the constructivism of duty. This paper will defend the “dignity of nonrational human beings” and justify a “strong” indirect duties regarding animals.