The introduction of liberal studies is a new curriculum reform initiative in Hong Kong starting from 2009. It is a kind of formal interdisciplinary curriculum built on decades of experiences garnered from the implementation of various integrated subjects with similar nature. Through the method of documentary analysis that brings all official policy papers, curriculum guides/documents, stakeholders' feedback, and prior research into critical scrutiny, this article aims to analyze the phylogeny of formal interdisciplinary curriculum in Hong Kong from historical, sociological, ideological, and curricular perspectives, with a view to delineating the changes and continuities in the development of interdisciplinary curriculum and identifying the problems and possibilities for its implementation.