This participatory action research aimed to 1) study the community participation 2) develop a model for community participation and 3) study the effectiveness of the community participation in behavior modification for diabetes prevention among diabetes risk group in Moo 1 Ban Lamchang, Khao Phrai Subdistrict, Ratsada District, Trang Province. The samples of study were 65 stakeholders and people aged 35 years and over, 37 people. The tools used in this research contain: community participation model had period is 8 weeks, questionnaire and questionnaire for focus group interviews. Data were analyzed by frequency, percentage, mean and standard deviation, wilcoxon signed rank test and content analysis.

               The results showed that 1) The overall community participation was at a high level (= 3.89±0.82). 2) The model of community participation consisted of 4 steps: participation in decision-making; public forum and focus group discussion, steps to participate in operations by workshops, exercises, food selection, home visits and prototype contest participatory steps to gain benefits, increase diabetes knowledge and preventive behaviors; and the process of participating in the evaluation by tracking exercise and assessing the progress of the health diary. 3) Effectiveness of the community participation model were knowledge, perceived severity and perceived benefits after the model were significantly higher than before the model at the 0.01 level, perceived obstacles and the blood glucose level after the model was significantly lower than before the model at the 0.01 level.