From the anthropological research study on the Tai speaking people found that the custom of ancestor worship is belonging to the ancient beliefs system. All Tai speaking people have the custom of worshipping the ancestors as gods in their own ways. There are a lot of important rituals for all Tais in mainland Southeast Asia, South China and North East India. The rituals show that they have their connection with the concept of the Kwan - Dam - Phi as prevalent amongst the people by the comparative view among them. This beliefs system in the divinity of the dead is an ancient one and it is said that ancestor worship is related to the idea of the soul living forever. After death, the soul would leave the body and go back to the place where their ancestors live. Many peoples offer sacrifices to “Heaven, earth, king, ancestor, teacher and others” and passed on to their offspring within their communities’ area. Whether Tais are influenced by other religions and developed to be the citizens of modern nation states; the ancestor worship still remains their cultural heritage as well.