From ancient times to the present day, Buddhist rituals and festival activities have been commonly seen on the Buddha’s Day. This essay examines the characteristics of the Buddha’s Day activities in Chinese Buddhism between 1912 and 1937, as well as its connection with Buddhist modernity. During this period, Chinese Buddhism experienced tremendous changes as new regimes replaced the rule of the Qing dynasty and attempted to promote secularization. With the development of industry and commerce, various types of lay organizations were established in towns and cities. The improvement of printing technology changed the medium of communication, and Buddhist periodicals, newspapers, books, and other publications became new ways of disseminating Buddhist ideas. In this process, activities related to the Buddha’s Day were also endowed with modernity significance. This essay will focus on the Buddha’s Day and analyze activities such as Buddhist preaching, releasing animals, verifying the date of the Buddha’s birthday, and Buddhist social participation during this period.