By examining the theory and methodology of studies "across disciplines", this article explores the "across-disciplines" character of Sino-Christian studies with regard to its practice and achievements. It points out that the implication of "across-disciplines" for Sino-Christian studies lies in moving from "multidisciplinary studies" in various aspects of Christianity to "interdisciplinary studies" in both the topics of Sino-Christian theology and the social public issues. This character contributes to the identity formation of Sino-Christian studies and its growth from and impact to Chinese academia as an independent discipline.