The four Āgama have long been regarded as canons of Hīnayāna Buddhism in China and, for that reason, neglected in scholarly circles. Recenly, however, they began to receive attention, especially the Saṃyukta Āgama, which is now regarded as one of the earliest Buddhist canons and is of vital importance to the study of early Buddhism in India. What makes Saṃyukta Āgama different from other three Āgamas is that it consists of thousands of gāthās. Studies in the past by and large turned their attention on the overview of gāthās found in sutras, and it is very rare for researchers to focus on the gāthās in one particular text. Based on the fifty-one "saṃyuktas" on various topics in Saṃyukta Āgama, this essay divides the gāthās into sixteen categories, including recapitulating sermons, exposition, question and answer, praise, conquest, preaching, reference, vigilance, realization, removing doubts, initiation, tests and trials, offering alms, funeral, incantation and narration. Examples are given to reveal their special features and functions , as well as to investigate the principles behind the compilation of the canon, with the hope of deepening the understanding of the early Buddhist canons in India.