The Yulanpen Festival (盂兰盆节), also known as the Ghost Festival or Ullambana, stands as one of China's most spiritually profound and culturally rich traditional observances. Rooted in the Buddhist Ullambana Sūtra and deeply influenced by Confucian ethics and Daoist cosmology, the festival centers on the value of filial piety and the enduring connection between the living and the dead. This paper examines the historical development, religious significance, and evolving practices of the Yulanpen Festival in both Chinese and diasporic contexts. Through its diverse rituals—including ancestral offerings, sutra chanting, and ritual operatic performances—the festival serves as a powerful expression of compassion, karmic redemption, and social cohesion. It also offers a compelling example of how ancient religious traditions adapt and persist amid the forces of modernity. Drawing on historical texts, canonical scriptures, and ethnographic case studies from Hong Kong, this study highlights the Yulanpen Festival as a vital conduit for cultural continuity and spiritual renewal.