Abstract: The constitution of Thailand B.E. 2550 has enacted on the people participation for environment and the natural resource conservation on the different sections such as in Section 67 specified that the right of people to take participation in conservation, utilization, protect and promote the quality of environment and natural resources by living without causing a harmful effect and with concerning security and quality of life. If there is any activity that might affected to the quality of environment and the natural resources of the community forest such as clearing forest for farming or feeding cow in the community forest, the community people should have a right to protect. In case of the huge project such as a dam construction, the general people or the Non-government Organization (NGO) should have the right to participate in the public hearing and to give the opinions before the project implementation occurrence. The objective of this study was to formulate the Community Forest Act for Thailand based on the people participation. The mixed method of qualitative and quantitative approaches was done. The in-depth interview with structural form was implemented for data collection from the stakeholders which included the community environmental leaders of Bann Kaeng- Ka-Arm, the Tambon Administration Organization (TAO) members of Pa-Sa-Weoy, Ampoe Somdej, Kalasin province and the NGO. The Participatory Appreciate-Influence-Control technique (PAIC) was used in the brain storming session of community peoples to formulate the Community Forest Act for Thailand. Considering to the in-dept interview of the stakeholders which included the community environmental leaders, the TAO members and the NGO, it was found that most of them agreed that there is a serious conflict problem between the community people and the governmental sector due to the Act of Community Forest is not issued by parliament until now. Most of them agree that they would like to have the following contents in the formulate act of community forest. Community people should have the right to participate and manage for Community Forest Conservation if they are living before the announcement of the Act of National Park in B.E. 2504. Community people should have the authority to collect mushroom, herb, firewood and wood for household use and public use but they can not sell timber of community forest. The people outside the community have no right and authority like as community people who look after community forest before the announcement of forest conservation area . Community people should have duty to protect the biodiversity of community forest and etc. The results illustrated that before and after the PAIC process implemented, the knowledge achievement and the environmental participation were determined. It was found that there were high statistically significant difference between pre- and post-test in p<0.01 and p<0.01 in two aspects of knowledge achievement, environmental participation for community forest conservation. The mean scores between self- and friend-evaluation between friend- and facilitator-evaluation and between self- and facilitator-evaluation showed statistical difference (p<0.05, p<0.05 and p<0.01). During the PAIC was implementing, the 4 focus groups discussion were done. The overall results showed that there were at least 4 purposed projects such as knowledge given to people for Community Forest Conservation, Afforestation Conservation of Endangerus species of plants and animal and promotion people participation for Community Forest Conservation which would be implemented according to the action plans on Community Forest Conservation. These were implemented at the community. The pilot project was selected three from four proposed projects. These were knowledge given to people for Community Forest Conservation, Afforestation and promotion people participation for Community Forest Conservation. The PAIC had been urgently used to prevent the loss of biodiversity of community forest during they were waiting for the issuing of Community Forest Act. The recommendation from the finding is that the community people in each community forest all over the country should make a consensus in order to propose to the government and the parliament members for making a decision of issuing the Act of Community Forest as soon as possible. Finally, researchers can conserve the community forest with the real people participation.