The dissertation examines the theme of creation in science fiction from a cofuturistic perspective. Drawing extensively from literary works in both English and Chinese, it aims to study science-fictional representations of creation through multiethnic and transnational approaches. Posthumanism is adopted as a paradigm to propose a theory of creation which advocates new interpretations of human-nonhuman relationality. The theory of posthuman creation deconstructs anthropocentrism and situates humans among other agents in the web of creation. Both the human and the nonhuman are co-creators contributing to the co-creation of new entities. On the one hand, posthuman creation elucidates the theme of creation in science fiction; on the other hand, works of science fiction contribute to the theorization of posthuman creation. The theme of creation in science fiction is investigated in five aspects. First, the relationship between the procreativity of nature and the creativity of humans is examined through the analysis of the womb motif. Second, the materiality of creations is viewed from a comparative perspective to reveal the cultural dimension of creative materials. Third, posthuman relationality is explored to study the intricate relationship between creators and creations. Fourth, intentionality, agency and control are scrutinized from a posthuman perspective to problematize the anthropocentric conceptualization of human creation. Five, co-intelligence and co-creativity are theorized to redefine intelligence and creativity in an age of creative AIs. By contextualizing the creative activities of humans and nonhumans in science fiction, the dissertation points to an understanding of creativity that is illuminated by posthumanism, cofutures and emerging technologies of creativity.