As a complicated phenomena, religious conversion was studied by social science interdisciplinary, such as psychology, sociology, and anthropology. The psychologist tends to focus primarily on the isolated individual who is converting. The sociologist likes to see conversion as the result of forces shaped and mobilized by social institutions and mechanisms. The anthropologist thinks that conversion is the product of culture. Because every discipline has its research tradition, it is hard to take integrative point of view to explore the processes of religious conversion. This study was designed from the holistic perspectives, which focus on cultural, social, individual, and religious system, to investigate the conversion in Buddhism. The qualitative in-depth interview will be adapted to collect data, and the data will be analyzed by the procedure of grounded theory. The preliminary model of conversion processes will be built up then.