"Amalgamation of Sasana-Phi into Buddhist Culture of Lao: A Study of its Impact And Significance," is focused on the Amalgamation of Sasana-Phi on Buddhism in Lao cultures, traditions, and festivals even in every aspect of the Buddhist monks and lay devotees' ritual practice from the ancestral time to the present day. Along with this, I will briefly explain the overview of Pre-Buddhism at the time of the Lane Xang Kingdom, how Buddhism spread to the land of Lane Xang Kingdom and what was the basic teaching of Buddha. This book also aims to explore the introduction of Buddhist ideology on the Lao population, which comes from an earlier time. Moreover, I also mentioned various points of view about the concept of ghost ancestor ritual practice, the way of practice of ghost ancestor ritual, and the myth of Guardian spirits like the concept of Naga/ Payanak (big serpent). Moreover, the critical highlight ritual concepts practice of Sassana-Phi such as the Lao New Year Festival, the Baci ceremony, the concept of the U-Tid-SuanBoun (transfusion of merits to the ancestor's spirits), the concept of Kan-Lieng-Phi (Offering to the ghost) along with the practice of worshipping the ghosts, the Nang Thiem (the worship of the ghost through dance performance), the practice of animal sacrifice to the spirits and other festivals which related to the Sasana-Phi ritual concepts practice. And the last, I will discuss the combination of Sasana-Phi and Buddhism practice and the other religions existing in Laos.