Despite the amazing advancements in the studies on the history of Chinese folk religion, there appears to be very little systematic discussion and research on the transgendering of Avalokiteśvara during the pre- Sung period and the emerging of "Three Pure Ones" of Manichaeism. This research aims to answer those questions by analyzing relevant literature. This study hypothesizes that the transgendering of Avalokiteśvara should have started from the very beginning of the Tang dynasty, and "Manichaeism Trinity" have transformed into Taoism- like "Three Pure Ones" during the Ming- Ch'ing period, which are of the bijective relation to each other.