Abstract: The evolution of Buddhist and Daoist hagiographies in medieval China manifested a trend of interaction and integration. Both indigenous Daoist immortal hagiographies and Buddhist monk hagiographies drew their stylistic frameworks and writing techniques from historical biographical works, laying the foundation for their mutual engagement. Their interaction fall into two categories. The first inherits the traditional historical biographical style. Traditions of Divine Transcendents bears no evident traces of Buddhist influence, while the Inter Hagiographies of Upper Clarity began absorbing Buddhist narrative features in depicting supernatural appearances of immortals. Meanwhile, Hagiographies of Eminent Monks borrowed substantially narrative patterns from Daoist immortal hagiographies. The second breaks away from conventional historical biographical norms. Ling-pao Scriptures and Hagiographies comprehensively assimilated and rewrote translated Buddhist hagiographies. Inner Hagiography of Wen Shi compiled by the Louguan School in the Northern Dynasties marked the culmination of pre-Tang exchanges between Buddhist and Daoist biographical writings. In content depiction, Buddhist hagiographies excel in portraying human nature, attributable to the role of Daoist hagiographies in constructing doctrinal systems of emerging Daoist schools. Stylistically, Daoist hagiographies feature more parallel prose and vivid imagery, shaped by the belief that such texts were translated from celestial scriptures and their esoteric nature. Examining medieval literature from the perspective of Buddhist-Daoist interaction helps reveal the authentic trajectory of literary development.