The Yi are animists, with elements of Daoism, shamanism and fetishism. Shamans/medicine men are known as “Bimo”ꀘꂾ (official transcription: bi mox; proximate French pronunciation: pimo), which means the master who can chant ancient documents. Bimo officiate at births, funerals, weddings and fetes. They are often seen along the street consulting ancient scripts. As animists, Yi worship the spirits of ancestors, fire, hills, trees, rocks, water, earth, sky, wind, and forests. Magic plays a major role in daily life through healing, exorcism, asking for rain, cursing enemies, blessing, divination and analysis of one's relationship with the spirits. They believe dragons protect villages against bad spirits, and demons cause diseases. However, the Yi dragon is neither similar to dragon in western culture nor the same as that in Han culture. After someone dies they sacrifice a pig or sheep at the doorway to maintain relationship with the deceased spirit.
The Nuosu religion (from the Nuosu or Nasu group in the Yi minority) distinguishes two sorts of shamans: the Bimo and the Sunyi ꌠꑊ(official transcription: su nyit; proximate French pronunciation: sougni). Bimo, who can read Yi scripts while Sunyi cannot, are the most revered and maybe also important agents in the Nuosu religion, to the point that sometimes the Nuosu religion is also called “bimo religion”. While one becomes a Bimo by patrilineal descent after a time of apprenticeship or formally acknowledging an old Bimo as the teacher, a sunyi must be elected. Both can perform rituals. But only Bimo can perform rituals linked to death. For most cases, Sunyi only perform some exorcism to cure diseases. Bimo are literate too. Generally, Sunyi can only be from humble civil birth while Bimo can be of both aristocratic and humble families. In order to preserve this heritage and promote tourism, the local government helped construct a museum to house ancient artifacts.
In Yunnan, some of the Yi have been influenced by Buddhism through the Han culture. The Yi believe in numerous evil spirits. They believe that spirits cause illness, poor harvests and other misfortunes and inhabit all material things. The Yi also believe in multiple souls. At death, one soul remains to watch the grave while the other is eventually reincarnated into some living form.
In the 20th century, some Yi people in China converted to Christianity, after the arrival of medical missionaries such as Alfred James Broomhall, Janet Broomhall, Ruth Dix and Joan Wales of the China Inland Mission. According to missionary organization OMF International, the exact number of Yi Christians is not known. In 1991 it was reported that there were as many as 150,000 Yi Christians in Yunnan Province, especially in Luquan County where there are more than 20 churches.
