Huayan Buddhism approaches the Avataṃsaka Sūtra as its foundational scripture, seeing in it not merely a collection of doctrines but the Buddha’s own direct enlightenment experience articulated in visionary form. The sutra is read as unveiling the dharmadhātu, the total realm of reality, in which the one universal principle (li) and the myriad phenomena (shi) are inseparable. This is expressed in the insight that “one is all, all is one”: each particular thing both manifests and contains the totality. The famous image of Indra’s Net, with its infinite jewels each reflecting all the others, becomes the emblem of this vision of perfect interpenetration and mutual containment. On this basis, Huayan treats the sutra as the most complete exposition of Buddhist truth, a text that discloses the cosmos as a single, boundless field of interdependence.

To clarify this vision, Huayan masters systematize the sutra’s teaching in terms of the fourfold dharmadhātu: the realm of principle, the realm of phenomena, the non‑obstruction between principle and phenomena, and the mutual non‑obstruction of phenomena with one another. In this reading, emptiness or suchness (principle) is not elsewhere than concrete things, and concrete things do not hinder one another; rather, each supports and defines all others. Interdependence is thus understood not only as sequential dependent origination but as simultaneous, mutual causation, where everything arises together in a single web of relations. This is what Huayan calls perfect interfusion: every element retains its distinctiveness while fully containing and expressing all others, without obstruction.

The Avataṃsaka Sūtra is also interpreted as revealing the body and world of the Buddha Vairocana as identical with the entire cosmos. The dharmadhātu itself is seen as the Buddha’s body, so that all beings and all phenomena participate in this vast Buddha‑realm. In this light, the doctrine of tathāgatagarbha is read as the affirmation that all beings possess Buddha‑nature within this interconnected web of existence, and that Buddhahood is not fundamentally separate from the world that is experienced. The universe described in the sutra is thus not a distant, otherworldly realm, but the true nature of this very world when seen from the awakened perspective.

At the same time, Huayan does not neglect the path of practice. The sutra’s detailed accounts of the bodhisattva path—such as the ten stages (bhūmi), the progressive practices, and the great vows of Samantabhadra—are taken as a map of how this reality is gradually realized. The journey of the bodhisattva is understood as the unfolding recognition of the already‑present interpenetrating world disclosed by the sutra. Through this lens, ethical conduct and compassion acquire a radical depth: to benefit one being is, in effect, to benefit the entire network of existence, and to harm one is to harm all. Huayan exegesis, especially in the works of figures like Fazang and Chengguan, thus reads every passage of the Avataṃsaka Sūtra as illustrating the same fundamental insight into the complete, unobstructed interdependence of all things.