《未來史》（Anāgatavaṃsa）是屬於後期的巴利語文獻，相傳是12世紀晚期的Kassapa 所編撰，為第一部完整描述彌勒從出生、成佛、涅槃一生事跡的著作。從它的組織和語句來看，與《長部．轉輪聖王師子吼經》和《佛史》相似度高，極有可能參考這二部經。但是有些語詞字句不見於這二部佛典中，作者很有可能參考別的語系彌勒典籍，如梵文等等。梵文等語系的典籍經過流傳而傳入中國，經由古德譯出成漢譯經典。這些漢譯經典中有多部描述彌勒下生人間成佛典籍，稱為「下生經」，目前收入於《大正藏》有五部之多。相較於目前梵文或其他語系的彌勒典籍數量較少的情況下，漢譯經典更顯得重要。因此，本篇論文即以文獻比對的方法將《未來史》與漢譯彌勒「下生經」從組織和內容二方面比對其異同。經過比對，結果發現《未來史》與漢譯彌勒「下生經」的一些語句非常相似，而且只見於漢譯「下生經」，而不見於巴利經藏。因此，推論作者可能所參考的經典與漢譯「下生經」存在著某種關係。

Anāgatavaṃsa belongs to the late period of Pāli literature. It describes Metteyya's life from his birth, awakening, preaching and nirvaṇa as a whole. According to the tradition the text was compiled by Kassapa in the late 12th century. There are some similarities between Anāgatavaṃsa, Cakkavattisīhanādasuttanta, and Buddhavaṃsa, regarding their narrative structures and sentence patterns. There are, however, some exceptions. One possible reason is that the author of Anāgatavaṃsa might have referred to other Metteyya suttas found in other languages. The variation of the extant Metteyya suttas in Sanskrit or other languages is very limited; the Chinese versions of the texts, however, exist in five different translations in the Taishō Tripiṭaka, thus become particularly important. Using the method of literature comparison, the objective of this article is to compare Anāgatavaṃsa with the five Chinese versions of Metteya suttas in order to identify their similarities. This comparison shows that there are certain similarities between Anāgatavaṃsa and the five Chinese Metteyya suttas in terms of the sentence patterns which are not observed between in the Cakkavattisīhanādasuttanta and Buddhavaṃsa. This indicates that there might be some relationships between Anāgatavaṃsa and the Chinese texts.