自《華嚴經》傳入後，中國以豐沛的文化當量，成功雜揉印度、西域文化，成就華嚴宗的璀璨，於此歷史背景孕育而生的「一乘不共別圓」乃華嚴思想體系的核心，以三教和五教統合論之，常與「一乘圓」混淆，而兩者間於行法的差異為最大的特徵，前者偏解脫道也是「一佛乘」，後者則偏圓融道。法界的概念則為「華嚴」的另一根本，就本元論分析，可將其分為體法界或稱一真法界和用法界或一心法界，體法界三觀多方已有論述，用法界則付之闕如，本文則試圖將一心法界分為世間法界、淨土法界、緣起法界和性起法界四部，並以「一心」和「法界」分別闡述為肇，次第解析法界真義。

Since the introduction of Avatamsaka Sutra, Huayan School has successfully integrated Indian and the Western culture with the rich culture in China and has achieved the prosperity of Huayan School. The ＂One Vehicle that contains all Truths＂ born in this historical background is the core of the Huayan system, with the integration of the ＂three Schools＂ thoughts and the ＂five Schools＂ thoughts. It is often confused with the ＂Buddhayana＂. The most significant difference between the two lies in the mana, the former one is more focused on liberation, which is also referred to as ＂One Buddha Vehicle＂, and the latter one is more focused on harmony. The concept of Dharmadhatu is another foundation of Avatamsaka. According to the analysis of Monism, it can be divided into the physical Dharmadhatu, or the A True Dharmadhatu, and usage Dharmadhatu, or the one-heart Dharmadhatu. The law concept of the physical Dharmadhatu has already been discussed by many researchers, while the research on the usage Dharmadhatu is still lacking. In this paper, I attempt to divide the one-heart Dharmadhatu into four parts: Dharmadhatu for the world, Sukhavati Dharmadhatu, origin Dharmadhatu, and Hsing Chi Dharmadhatu, and explain the meaning of the Dharmadhatu uses ＂one-heart＂ and ＂Dharmadhatu＂ respectively.