This thesis is aimed at studying origin and development of the tenth month festival appeared in Theravada Buddhist scriptures, origin and development of the tenth month festival of Surin Province, and Buddhist morals appeared in the tenth month festival of Surin Province. Methodology of this research is studying from Buddhist scriptures i.e. Tipitaka and Atthakatha, books, thesis, journals, online materials, and others concerned; tools for data collection are in-depth interview the ecclesiastical officials, the director of the office of Buddhism, the chairman of the cultural council, community leader, general people and the elderly in Surin province; analysis the data by description; and summary and discussion with narration. The research results are as follows:

                     The origin and development of the tenth month festival appeared in Theravada  Buddhist is as follows; the origin of the tenth month festival came from the belief of the ancient people on the power of sacred and mystery, they saw the happened phenomena as the willing of God. The  tenth month  festival was considered to be the significant ceremony of old and new Brahmanism which influenced the Brahmanism followers. The Buddhist tenth month festival was found to originate from the belief in making merit stories for the dead as seen in the Buddhist scripture such as King Pimpisan made a merit to dedicate to his relative hungry ghosts; Sariputtathera Bikkhu constructed monks’ four lodgings and offered food to the Sangha in dedication the merit to the hungry ghosts who used to be his mother; and Tissa Upasika offered food and Triple Robe to the eight Bikkhus and dedicated merits to the hungry ghosts. The said merit dedication made the dead free from the hungry ghost-hood. Such mentioned belief has been conducted up to the present time.

                     The origin and development of the tenth month festival of Surin province was originated for a long time, but has not found yet the exact time of origination. The tenth month festival of Surin province came from the belief in making merit to the dead as appeared in Buddhism. At the present time this festival is called “Saen Don Tar” which bring about many activities such as the ceremony of worshiping the ancestors, going to temple for making merits, the parade of procession on the street in the city which joined by both the state organizations and temples in Surin province. The tenth month festival of Surin province is usually organized two times in a year i.e. 1) Ben Tuj celebration (small tenth month festival) conducted on the waning moon day of the tenth lunar month, and 2) Ben Tom celebration (big tenth month festival) conducted on the waxing moon day of the tenth lunar month.

                The Buddhist morals appeared in the tenth month festival of Surin province is as follows; 1) the moral belief on merit such Dana Giving, Preservation of the Precepts, Well Wishing for self and others, and Making Merit for the Dead; 2) the moral belief on worshiping such as material  and practical worshiping, but the ancient moral belief is still seen like the killing of chickens, fish, and pigs for worshiping; 3) the moral belief on gratefulness i.e. ministering parents, ministering teachers, obeying, and reciprocation with the four requisites; 4) the moral belief on bases of social solidarity i.e. charity in the family and community.