This paper aims to design and validate a model for evaluation of educational aspect in distance education system. As an applied research, an exploratory mixed methods approach was used.  The participants in the qualitative study included 15 professors and researchers who were purposefully selected and interviewed. The statistical sample in the quantitative part of the study consisted of 215 managers, planners and experts of Payam Noor University Central Organization who were selected by convenience sampling and were asked to complete the research questionnaire. The questionnaire consisted of 52 indices whose content validity was evaluated by experts and its reliability was confirmed by Cronbach's alpha coefficient of 0.89. Open and axial coding was used to analyze the qualitative data, and confirmatory factor analysis was used in addition to the central tendency indices. The findings showed that a comprehensive model of educational evaluation in a distance education system consisted of following seven aspects: Organization, teacher, learner, pedagogy and technology generation, educational materials and content; educational methods and approaches; and learning time and place.  It also revealed that this model covers 52 indicators which can be used for evaluating educational aspects of the system via appropriate appraising methodology and tools