Hua-yen thought attracts great attention of the modern time but lacks reflection: Have the interpretations of "xing qi" (性起) deviated from the doctrine of Interdependent Co-arising (pratītya-samutpāda) and connected to the secular concepts of essence-function (體用)? In ancient times, the Hua-yen Patriarchs Zhiyan (智儼) and Fazang (法藏) adopted the indigenous East Asian concept of essence-function to analogically explain the term "ru lai xing qi" (如來性起) quoted from the Chinese translation of the Avataṃsaka-sūtra. After that, "xing qi" deprived of revolutionary spirit became sophistry like essentialism or pantheism in which laymen indulged. No wonder Matumoto Shiro considers the Hua-yen thought not Buddhist. Therefore, this article applies a bold hypothesis with careful verification on the interpretation of "xing qi": according to the linguistic meanings of the sanskrit title "tathāgata-utpatti-saṃbhava" (reconstructed on the basis of the Tibetan title by TAKASAKI Jikidō) of the Ru-lai-xing-qi chapter of the Avataṃsaka-sūtra, by taking Candrakīrti's viewpoint for the meanings of "cittamatra" (mind only) in Avatamsaka as the criterion for judging Zhiyan's and Fazang's interpretations of "xing qi," we can tell the "original meanings of scriptures" from the "analogical interpretations by Skilful Means" and reorganize the meanings of "xing qi." Fazang's disciple Huiyuan (慧苑) mentioned that "ru lai xing qi" can be a Karmadhāraya (descriptive determinative compound) as well as Tatpuruṣa (dependent determinative compound). The Chinese Buddhist scholars' interpretations of "xing qi" as a Tatpuruṣa favor the concepts of essence-function, hence this article attempts to make a train of thought by using Karmadhāraya interpretation. After understanding the synchronously presented concepts of Interdependent Co-arising and essence-function in Hua-yen patriarchs' commentaries on Avatamsaka, the author concludes: (1) Though Hua-yen patriarchs utilized the essence-function concept as Skilful Means to explicate the phenomenal realm and "xing qi," their ideas were still pointing to the doctrine of Interdependent Co-arising. Hence, there are traces of the original meanings of "xing qi" in the interpretation by Hua-yen patriarchs. (2) The contents of the Ru-lai-xing-qi chapter of the Avataṃsaka-sūtra are mainly describing "Buddha's awakening" and "Bodhisattva's awareness of Buddha" instead of the manifestation of Buddha's physical body, and, correspondingly, Hua-yen Patriarchs' interpretations of "xing qi" are mostly talking about "rising of the awakened mind." It is thus clear that the word "qi" (which literally means rising) in "ru lai xing qi" should be pointing to the "subject" (mind) instead of the "object" (phenomenon). Hua-yen Patriarchs' realization for "xing qi" is in concert with Candrakīrti's for "cittamatra", pointing to the "subjectivity" of "mind". (3) The "ru lai xing qi" teaching is about spiritua