The aims of this research study developed a model evaluation to assess the activity development of students in the Primary Education level in Thailand. The research was conducted by the research and development (R&D) process that it was administered in two phases; to investigate on analyzes the concept of student development activities, assessment of student development activities in primary school classes, and theory-driven evaluation and interviews with those involved with the activities of the students was the first phase. The second phase, creating an evaluation model to assess activity development for primary educational students. The third phase, to trial evaluation model by experimenting with different sized schools which sample consisted of nine schools, including small, medium, and expansion opportunity schools. The fourth phase, to assess the evaluation model that it has developed the tools used to assess the valuation model based on the evaluation of standards development committee to evaluate educational standards. The assessment is the evaluation of the experiment involving 18 experiments. It has found that; to investigation evaluated the events and activities of the primary educational students composed of textbooks, academic papers, the report showed that the factors used to evaluate the activity development of primary students in three key areas: planning activities for developing learners, processing development activities’ learners, and the characteristics of learners were satisfied. The evaluation model to evaluate activity development of primary educational students composed of eight elements, such as; principal, purpose, to be aimed at assessing the objective things, the tools used to evaluate, users assessment form, how to analyze assessment results, evaluation criteria, and assessment report. The experimental evaluation model to evaluate the activity development of primary educational students, the research study has found that expert on the evaluation model has given their opinions on the assessment form. The results are at the high appropriate level in all aspects and all indications are 3 aspects to planning development activities, process development activities for learners, and the quality characteristics of the students. The trial has not found of problems in the form of assessment. Finally, the developing evaluation model to evaluate activity development of primary education students, this is a theoretical validity, the opinions’ experts opine that the item can be measured according to measurement higher than 80%, and the possibilities are appropriate, and to be accurately, comprehensively.
