Abstract: John Baird Callicott is an important successor and interpreter of earth ethics, and provides the theoretical basis for earth ethics as a rigorous philosophical theory. Although scholars at home and abroad have made in-depth research on Callicott's environmental ethics from various angles, they have not explored the fundamental theoretical premise of Callicott, that is, the unity of worldview and values. Moreover, based on the fundamental theoretical premise of the unity of worldview and values did Callicott explain and defend the earth ethics. In order to make up for the research gap in academic circles, this paper analyzes the point of the unity of worldview and values in Callicott's environmental ethics, and explores how it can be used as the theoretical premise of Callicott to explain and defend the earth ethics.