In 2001, China's moral education curriculum reform called for a "returning to life" as a radical shift from its previous empty sermonic pedagogy, hoping to cultivate its twenty-first century children into ethical humans. Accordingly, a notion of "human ecology" appeared in the post-2001 textbook design, which became "co-being with" in the latest 2016 textbook redesign. This paper picks up this "co-being with" as a philosophical, ethical, and ecological notion and scrutinizes its relevance to the discursive construction of China's moral child in two steps. First, it draws upon Heidegger's thinking and the Chinese Daoist ecological understanding to explicate the philosophical significance of this "co-being with" for moral education. Second, it unpacks the discursive embodiments of this ethical-ecological "co-being" with in connection with the construction of moral subjects in the post-2001 and 2016 textbooks. Through rigorous textual analysis, this paper finds that the post-2001 textbook discourses embody an instrumental trope and a subject vs object binary style of reasoning, which possibly makes egoistic rather than ethical children. The 2016 textbook discourses, especially those on the theme of "co-being with," however, constrain the above instrumentality and envision cultivating ethical children. This paper argues this theorized "co-being with" provides some implications for moral education in China and the world, meanwhile raising some pedagogical challenges as well.