This research aimed to: 1) study current situations and problems of academic affairs administration system in Primary Schools. 2) develop an effective academic affairs administration system, and 3) evaluate the implementation of the developed system in the primary school, Thailand. Research and Development (R&D) was employed which consisted of the analysis of the current states and problems of the academic affairs administration system in primary schools, designing and verification of the developed system by experts, and implementation and evaluation of the developed system. The survey was used to analyze the current states and problems by 750 respondents as the samples, including school administrators and heads of academic affairs. The developed system was verified by nine experts. The developed system implementation was evaluated and informed by eleven school administrators and teachers. The research instruments included: questionnaires, evaluation form, semi-structured interview form, and school record form. The results showed that current situations of Thai primary schools academic affairs administration system, the practices were at high level, and the problems were at moderate level. The developed academic affairs administration system consisted four main aspects and among those there were nineteen components; the input aspect was comprised of six components, the process aspect comprised of eight components, the output aspect comprised of three components and the feedback comprised of two components. The usage of developed academic affairs administration system could significantly improve the students’ quality in higher level. In addition, administrators and teachers had satisfaction in system use.