This thesis had the following objectives: (1) to study the history of the ecclesiastical honorific rank of Thai Sangha (2) to study the works, criteria, qualifications method to receive the ecclesiastical honorific rank from the king, and (3) to study the roles and works of ecclesiastical honorific rank administrative officers in Khon Khaen province towards Thai social development. This was a documentary research by using descriptive method to find for the summary and suggestions.

                      The result of this research study was found that the tradition of offering the ecclesiastical honorific rank to Thai monks was derived from Srilanka. It had been developed from the past to present. The ecclesiastical honorific rank had many values to Thai societies, i.e. fine arts, such as, ecclesiastical fan, aesthetics and mental values. For example, Buddhist followers honored the monk who had ecclesiastical fan.

      There were values of language culture such as the new religious title name and official palace language. There were values of preservation such as almsgiving of the king and supporting a monk who had knowledge and social works.

      There were values of economics. It made merchants(sellers) to have income from selling Buddhist monk commodities. There were values of social aspects. There were the ecclesiastical honorific rank cerebration, it made monk who cerebrated proud of him.

      There were values of relations to the Buddhist countries. There were the ecclesiastical honorific rank offering to the monks from different countries i.e. Srilanka Myanmar Bangladesh etc. The Buddhist monk who would like to ask for an ecclesiastical honorific rank must have 6 works in according to criteria of the Sangha Supreme Council. The Steps of an ecclesiastical honorific rank to confer the an ecclesiastical administrative officers were as follows :-

                The criteria, qualifications, and ecclesiastical education to receive the ecclesiastical honorific rank from the king found that there were not only the qualifications and works according to six works of the Sangha supreme council. If ecclesiastical administrative officers had Pãli grade 7-9, he had qualified to be the first grade of Phãrãjagaṇa (Chao Khun). If he had Pãli grade 5-6, he had qualified to be Phra Khru grade 3 (Chan Ek). If he had B.A., B.Ed. degree, he had qualified to be Phra Khru with specal  grade. (Chanpiset) ). If he had Pãli grade 3-4, he had qualifed to be Phra khru grade 2(Chan Tho). If he had B.A., B.Ed. or M.A. he had qualified to be Phra khru grade 3 (Chan Ek). If he had Ph.D. degree, he had qualified to be Phra Khu with special grade (Chan Piset). Others qualifications for the ecclesiastical honorifict rank who had prominent works in the burden of the books and meditation, it was special qualification to get ecclesiastical honorific rank from the king etc.

      To receive religious title, made monks (to) have moral support in the social and religious working. The roles of the ecclesiastical honorific rank according to six aspect works to Thai social development were found that ruling aspect, the ruling principles, the rulers must have authority and gratefulness.

      The ecclesiastical honorific rank was very important and necessity to the rule. It made monks and lay followers pay respect them and it was easily to rule. The monk who had an ecclesiastical honorific rank must have goodness as well.

      The ecclesiastical education aspect:- almost temples have an ecclesiastical studies  i.e. Dhamma and Pali, some temples also have an ecclesiastical general education school. The methods to support education for the ecclesiastical administrative officers were supporting the four necessities of life and offer scholarship to students atc. The problems of an ecclesiastical education management at present were a few children and youth ordained. Monk  and Novices had no stimulation to study Dhamma and Pali. So, the Sangha Supreme Council have to reform the process of leaning, teaching, curriculum, measurement and evaluation   for standard more than today.

                      Welfare educational aspect :-  Some temples had Buddhist Sunday school, charily school from kindergarten up to the upper secondary level. The ecclesiastical administrative officers had many methods for educational supporting, such as, grant scholarship to students etc. The problem fund was not enough, so, they had raid the fund from Buddhist followers.

                      Propagation aspect :- There were models of Buddhist   propagation, such as, sermon, Dhamma lecture, moral training camp for children and youth, Dhamma book printing etc. The good propagators have to follow the five qualities of preacher and have proper techniques to preach.

                      Public building construction aspect :- construction and renovation about religious buildings and others. If the temple is located in the city, it better than out of the city, because people have good economy than the rural area. There was problem construction, for example, money was not enough for the construction and some builders took the advantage of temple. Almost the abbots made the religious buildings and others as the criteria and some were over the criteria fixed by the Sangha Supreme Council.

                      Public benefit making aspect : there were many models for making public service of monks, for examples, bridges, schools, hospitals, public health centre and donated some money or necessities of life for the victims and poor people etc.