The belief of worshiping Thien Hau (Mazu) originated from Fujian (China), following in the footsteps of Chinese immigrants, spreading many lands in Southern Vietnam. In the Mekong Delta, there are more than 50 Thien Hau shrines built by Chinese and Vietnamese and organized religious activities. In the minds of the plain people, Thien Hau is both a god and a guardian, but also a blessed being, a merciful mother, received by the Vietnamese through Buddhism and the worship of mother goddesses of Vietnam. Thien Hau's religious activities in the Mekong Delta show both Chinese cultural identity and a living proof for the process of multicultural mixing of the people of this land. This book introduces the process of worship of Thien Hau in China; Propagation and localization in Vietnam; Situation and influence of this belief in the Southwest region.