The play Guanyin’s Ascetic Days in Xiangshan in Ming legend-drama is a Buddhist drama about Princess MiaoShan, a legendary figure in Buddhism. The play is based on Jiang ZhiQi’s The Legend of Guanyin’s Enlightenment, later written down by Cai Jing and scripted on a stone monument that nowadays still stands in Guanyin Stupa, Xiangshan Temple, Baofeng County, Henan Province, China. The work covers the evolution of Guanyin’s legend: from the Dharmakaya of Bodhisattva of Compassion, to the reincarnated princess, MiaoShan, and later, to the formation of the thousand-handed & thousand-eyed Bodhisattva in Esoteric Buddhism. In the script of Guanyin’s Ascetic Days in Xiangshan, the main themes of Guanyin’s ascetic practice are mainly Mahayana teachings. Yet, a complete version of the “Universal Gateway Section”, Saddharmapundarika Sutra (the Dharma-flower sutra), was kept in this Ming legend-drama for ritual reference. It implies that the vertical practice of Esoteric Buddhism is still based on the theories of Exoteric Buddhism. With both schools complement each other, a complete system of vertical practice, “Root, Path, Fruit” is thus formed. As a result, the present research starts with the background when the “Universal Gateway Section”, Saddharmapundarika Sutra (the Dharma-flower sutra) was translated into Chinese. Thus, Sutras about Guanyin and about the thousand-handed & thousand-eyed Bodhisattva that are translated in Tang Dynasty are analyzed in this study. The most important research material in this thesis is The Legend of Guanyin’s Enlightenment: The Legend of Princess MiaoShan, written by Jiang ZhiQi in Song Dynasty. The teachings of both Exoteric and Esoteric Buddhism are also under careful examination to conduct a more thorough study.