Primary education is one of the important social sectors in the developing countries. It plays a gigantic role in promoting the social development of the concerned countries. More specifically, not the only education but the quality primary education which depends on such factors will contribute a lot for its smooth acceleration. In primary education, if the quality will maintain then automatically all the problems in primary education i.e. enrollment, completion, drop-out and so on will be robotic and gradually solved. The improvement primary education is influenced by both multiple qualitative and quantitative factors. This paper presents evidential reasoning(ER) approach to find out significant factors that are aggregated in assessment of performance of primary education. A case study of Dhaka, Chittagong, Rajshahi and Khulna districts in Bangladesh is provided to illustrate the implementation process of the ER approach for finding strong factors of primary education. For that reason, firstly we assess the performance of four districts then we determine the weakness and strength of specific factors of particular district. In this paper we also show the relation of lowest or best performing districts to its specific factors.