Maitreya Bodhisattva currently resides in Tuṣita Heaven and is the practitioner destined to attain complete enlightenment (samyaksaṃbodhi) after Śākyamuni Buddha. The concept of Maitreya Bodhisattva's future buddhahood emerged before the development of Buddhist schools and gradually became a consensus within the Buddhist community. This paper builds upon the research conducted by Master Yin-shun and primarily examines the Mahāvibhāṣā Śāstra, a crucial treatise of the Sarvāstivāda school. It explores four main themes: Maitreyadattaputra, Maitreya Bodhisattva, Maitreya Tathāgata, and Maitreya as a True Bodhisattva. Through these themes, it elucidates the characteristics of Maitreya Bodhisattva and the influence of Future Buddha thought on the śāstric scholars.