Tu-An-Hieu-Nghia is an indigenous religion located in Tri Ton district (An Giang province), which has grown for over one hundred years. The district is considered a holy site of this religion with a large number of followers, worship establishments and it also hosts major religious rituals. The rituals are held every month. There are 23 grand rituals in total (birthday and death day of Bon Su Master, birthday of the religion, worship of Trum Buddha,Trai Đan, etc.) held at the pagoda, while other rituals of Ky Yen, Lap Mieu are held at the communal house, Cau An at the temple, Chanh and Doan Ngu at Tam Buu’s house. These rituals reflect both religious beliefs and spiritual values of the followers’ lifestyles. However, they have undergone variations caused by the current times. This article will first introduce the performances of religious rituals at the worship establishments of this religion, followed by changes and causes in these rituals. Thus, it contributes to update knowledge of religion in An Giang province.