This research aims to: 1) synthesize knowledge regarding environmental management through the cultural introduction to Tha Poetry by the indigenous Pga K'nyau people in Chiang Mai province; 2) develop a manual for the cultural restoration participatory learning process to promote environmental sustainability conservation of ethnic students in Chiang Mai province; and 3) study the satisfaction towards the manual for the cultural restoration participatory learning process to promote environmental sustainability conservation of ethnic students in Chiang Mai province. This research is a Participatory Action Research (PAR) study. The samples used in the research consist of 1) a knowledge-providing group on Tha poetry, comprising 5 local Pga K'nyau scholars; 2) a manual assessment group consisting of 5 Pga K'nyau environmental knowledge experts; and 3) a trial group for the learning process, comprising 30 Pga K'nyau ethnic student teachers. The tools used in the research include 1) unstructured interviews; 2) a manual quality assessment form for Tha poetry of Pga K'nyau to promote environmental conservation; and 3) a satisfaction questionnaire. The qualitative data were analyzed using content analysis, and the quantitative data were analyzed by finding the mean and standard deviation. The research found that: 1) The synthesis of knowledge concerning environmental management through the cultural introduction on Tha Poetry among the indigenous Pga K'nyau people in Chiang Mai province revealed that Tha serves as a poetic introduction reflecting the life and existence of the Pga K'nyau. "Tha" holds significance for everyone, acting as a medium for transmitting knowledge and wisdom. It is a poetic introduction that melds life, experiences, teachings, and memories from the older generation, being recited in every ceremony from weddings, pre-marital counseling, gender role socialization, New Year celebrations, guest receptions, blessings requests, illnesses, to funerals. The content of Tha thus encapsulates the relationships between individuals, between humans and nature, and between humans and supernatural forces. The Pga K'nyau people emphasize environmental conservation, believing that nature has local deities who protect and look after the area. Furthermore, there's a tradition of transmitting knowledge through Tha Poetry for environmental conservation to achieve sustainability. This document has been created to revive the knowledge embedded in the cultural introduction of Tha, a heritage of wisdom passed down through generations, for the training and education of descendants, delving deeply into the conservation of natural resources and the environment. This ensures that individuals studying this will gain understanding from the teachings of the Pga K'nyau community. Currently, the practice of reciting Tha Poetry has been diminished, necessitating adaptation and conservation to preserve Tha in the culture of the Pga K'nyau people. 2) The development of a manual for the cultural restoration participatory learning process on Tha Poetry to promote environmental sustainability conservation of ethnic students in Chiang Mai province revealed that the manual comprises the meaning of Tha, Tha poetry sections for promoting environmental conservation through synthesis, and activity sheets for learning Tha poetry to promote the environmental sustainability conservation. The manual has a highly appropriate learning standard level. 3) The study on satisfaction towards the manual for the cultural restoration participatory learning process on Tha Poetry to promote environmental sustainability conservation of ethnic students in Chiang Mai province found that the majority of the students expressed satisfaction towards the manual, indicating that it is clear and highly beneficial for learning, rating it from high to the highest level.